diff --git a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests.java b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests.java
index 53f5181abbd..17c6eab37e7 100644
--- a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests.java
+++ b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests.java
@@ -606,7 +606,7 @@ public void testCamelCaseField1() throws JavaModelException {
 }
 // https://bugs.eclipse.org/bugs/show_bug.cgi?id=102572
 public void testCamelCaseLocalVariable1() throws JavaModelException {
-	String old = getSetCodeAssistProperty(JavaCore.CODEASSIST_VISIBILITY_CHECK, JavaCore.ENABLED);
+	String old = getSetCodeAssistProperty(JavaCore.CODEASSIST_CAMEL_CASE_MATCH, JavaCore.ENABLED);
 	try {
 		this.workingCopies = new ICompilationUnit[1];
 		this.workingCopies[0] = getWorkingCopy(
@@ -26221,4 +26221,200 @@ public void test() {
 					+ "}",
 			requestor.getResults());
 }
+public void testGH2620_1() throws JavaModelException {
+	this.workingCopies = new ICompilationUnit[1];
+	this.workingCopies[0] = getWorkingCopy("/Completion/src/GH2620.java", """
+			public class GH2620 {
+				public static void main (String[] args) {
+					Test local;
+					if (true) { // the if-statement is crucial for this test.
+						/*x*/local.ref.test();
+					}
+				}
+				public static class Test {
+					public Test ref;
+					public static void test() {}
+				}
+			}
+			""");
+	CompletionTestsRequestor2 requestor = new CompletionTestsRequestor2(true, true, true, false);
+	String str = this.workingCopies[0].getSource();
+	String completeBehind = "/*x*/local.ref.te";
+	int cursorLocation = str.indexOf(completeBehind) + completeBehind.length();
+	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
+	int relevance = R_DEFAULT + R_RESOLVED + R_INTERESTING + R_CASE + R_NON_RESTRICTED;
+	assertResults(
+		"test[METHOD_REF]{test(), LGH2620$Test;, ()V, null, null, test, null, [157, 164], "+relevance+"}",
+		requestor.getResults()
+	);
+}
+public void testGH2620_1a() throws JavaModelException {
+	// to observe the difference when cursor is right to '('
+	this.workingCopies = new ICompilationUnit[1];
+	this.workingCopies[0] = getWorkingCopy("/Completion/src/GH2620.java", """
+			public class GH2620 {
+				public static void main (String[] args) {
+					Test local;
+					if (true) { // the if-statement is crucial for this test.
+						/*x*/local.ref.test();
+					}
+				}
+				public static class Test {
+					public Test ref;
+					public static void test() {}
+				}
+			}
+			""");
+	CompletionTestsRequestor2 requestor = new CompletionTestsRequestor2(true, true, true, false);
+	String str = this.workingCopies[0].getSource();
+	String completeBehind = "/*x*/local.ref.test(";
+	int cursorLocation = str.indexOf(completeBehind) + completeBehind.length();
+	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
+	int relevance = R_DEFAULT + R_RESOLVED + R_INTERESTING + R_EXACT_NAME + R_CASE + R_NON_RESTRICTED + R_UNQUALIFIED;
+	assertResults(
+		"test[METHOD_REF]{, LGH2620$Test;, ()V, null, null, test, null, [163, 163], "+relevance+"}",
+		requestor.getResults()
+	);
+}
+public void testGH2620_1b() throws JavaModelException {
+	// to observe argument proposal
+	this.workingCopies = new ICompilationUnit[1];
+	this.workingCopies[0] = getWorkingCopy("/Completion/src/GH2620.java", """
+			public class GH2620 {
+				public static void main (String[] args) {
+					Test local;
+					int j = 1;
+					if (true) { // the if-statement is crucial for this test.
+						/*x*/local.ref.test();
+					}
+				}
+				public static class Test {
+					public Test ref;
+					public static void test(int i) {}
+				}
+			}
+			""");
+	CompletionTestsRequestor2 requestor = new CompletionTestsRequestor2(true, true, true, false);
+	String str = this.workingCopies[0].getSource();
+	String completeBehind = "/*x*/local.ref.test";
+	int cursorLocation = str.indexOf(completeBehind) + completeBehind.length();
+	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
+	int relevance = R_DEFAULT + R_RESOLVED + R_INTERESTING + R_EXACT_NAME + R_CASE + R_NON_RESTRICTED;
+	assertResults(
+		"test[METHOD_REF]{test(), LGH2620$Test;, (I)V, null, null, test, (i), [170, 177], "+relevance+"}",
+		requestor.getResults()
+	);
+}
+public void testGH2620_1c() throws JavaModelException {
+	// to observe argument preservation
+	this.workingCopies = new ICompilationUnit[1];
+	this.workingCopies[0] = getWorkingCopy("/Completion/src/GH2620.java", """
+			public class GH2620 {
+				public static void main (String[] args) {
+					Test local;
+					int j = 1;
+					if (true) { // the if-statement is crucial for this test.
+						/*x*/local.ref.test(1);
+					}
+				}
+				public static class Test {
+					public Test ref;
+					public static void test(int i) {}
+					public static void test2() {}
+				}
+			}
+			""");
+	CompletionTestsRequestor2 requestor = new CompletionTestsRequestor2(true, true, true, false);
+	String str = this.workingCopies[0].getSource();
+	String completeBehind = "/*x*/local.ref.test";
+	int cursorLocation = str.indexOf(completeBehind) + completeBehind.length();
+	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
+	// argument preservation can be observed by the replacement range which should only cover the method name:
+	assertResults(
+		"""
+		test2[METHOD_REF]{test2, LGH2620$Test;, ()V, null, null, test2, null, [170, 174], 49}
+		test[METHOD_REF]{test, LGH2620$Test;, (I)V, null, null, test, (i), [170, 174], 53}
+		""".strip()
+		,
+		requestor.getResults()
+	);
+}
+public void testGH2620_2() throws JavaModelException {
+	this.workingCopies = new ICompilationUnit[1];
+	this.workingCopies[0] = getWorkingCopy("/Completion/src/GH2620.java", """
+			public class GH2620 {
+				public static void main (String[] args) {
+					Test local;
+					/*x*/local..test(); // cursor is tested for between the dots: "local.|.test();"
+				}
+				public static class Test {
+					public Test ref;
+					public static void test() {}
+				}
+			}
+			""");
+	CompletionTestsRequestor2 requestor = new CompletionTestsRequestor2(true, true, true, false);
+	String str = this.workingCopies[0].getSource();
+	String completeBehind = "/*x*/local.";
+	int cursorLocation = str.indexOf(completeBehind) + completeBehind.length();
+	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
+	assertResults("""
+		test[METHOD_REF]{test(), LGH2620$Test;, ()V, null, null, test, null, [92, 92], 49}
+		clone[METHOD_REF]{clone(), Ljava.lang.Object;, ()Ljava.lang.Object;, null, null, clone, null, [92, 92], 60}
+		equals[METHOD_REF]{equals(), Ljava.lang.Object;, (Ljava.lang.Object;)Z, null, null, equals, (obj), [92, 92], 60}
+		finalize[METHOD_REF]{finalize(), Ljava.lang.Object;, ()V, null, null, finalize, null, [92, 92], 60}
+		getClass[METHOD_REF]{getClass(), Ljava.lang.Object;, ()Ljava.lang.Class;, null, null, getClass, null, [92, 92], 60}
+		hashCode[METHOD_REF]{hashCode(), Ljava.lang.Object;, ()I, null, null, hashCode, null, [92, 92], 60}
+		notify[METHOD_REF]{notify(), Ljava.lang.Object;, ()V, null, null, notify, null, [92, 92], 60}
+		notifyAll[METHOD_REF]{notifyAll(), Ljava.lang.Object;, ()V, null, null, notifyAll, null, [92, 92], 60}
+		ref[FIELD_REF]{ref, LGH2620$Test;, LGH2620$Test;, null, null, ref, null, [92, 92], 60}
+		toString[METHOD_REF]{toString(), Ljava.lang.Object;, ()Ljava.lang.String;, null, null, toString, null, [92, 92], 60}
+		wait[METHOD_REF]{wait(), Ljava.lang.Object;, ()V, null, null, wait, null, [92, 92], 60}
+		wait[METHOD_REF]{wait(), Ljava.lang.Object;, (J)V, null, null, wait, (millis), [92, 92], 60}
+		wait[METHOD_REF]{wait(), Ljava.lang.Object;, (JI)V, null, null, wait, (millis, nanos), [92, 92], 60}
+		""".strip()
+		,
+		requestor.getResults()
+	);
+}
+public void testGH2620_3() throws JavaModelException {
+	this.workingCopies = new ICompilationUnit[1];
+	this.workingCopies[0] = getWorkingCopy("/Completion/src/GH2620.java", """
+			public class GH2620 {
+				public static void main (String[] args) {
+					Test local;
+					if (true) { // the if-statement is crucial for this test.
+						/*x*/local..test(); // cursor is tested for between the dots: "local.|.test();"
+					}
+				}
+				public static class Test {
+					public Test ref;
+					public static void test() {}
+				}
+			}
+			""");
+	CompletionTestsRequestor2 requestor = new CompletionTestsRequestor2(true, true, true, false);
+	String str = this.workingCopies[0].getSource();
+	String completeBehind = "/*x*/local.";
+	int cursorLocation = str.indexOf(completeBehind) + completeBehind.length();
+	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
+	assertResults("""
+		test[METHOD_REF]{test(), LGH2620$Test;, ()V, null, null, test, null, [153, 153], 49}
+		clone[METHOD_REF]{clone(), Ljava.lang.Object;, ()Ljava.lang.Object;, null, null, clone, null, [153, 153], 60}
+		equals[METHOD_REF]{equals(), Ljava.lang.Object;, (Ljava.lang.Object;)Z, null, null, equals, (obj), [153, 153], 60}
+		finalize[METHOD_REF]{finalize(), Ljava.lang.Object;, ()V, null, null, finalize, null, [153, 153], 60}
+		getClass[METHOD_REF]{getClass(), Ljava.lang.Object;, ()Ljava.lang.Class;, null, null, getClass, null, [153, 153], 60}
+		hashCode[METHOD_REF]{hashCode(), Ljava.lang.Object;, ()I, null, null, hashCode, null, [153, 153], 60}
+		notify[METHOD_REF]{notify(), Ljava.lang.Object;, ()V, null, null, notify, null, [153, 153], 60}
+		notifyAll[METHOD_REF]{notifyAll(), Ljava.lang.Object;, ()V, null, null, notifyAll, null, [153, 153], 60}
+		ref[FIELD_REF]{ref, LGH2620$Test;, LGH2620$Test;, null, null, ref, null, [153, 153], 60}
+		toString[METHOD_REF]{toString(), Ljava.lang.Object;, ()Ljava.lang.String;, null, null, toString, null, [153, 153], 60}
+		wait[METHOD_REF]{wait(), Ljava.lang.Object;, ()V, null, null, wait, null, [153, 153], 60}
+		wait[METHOD_REF]{wait(), Ljava.lang.Object;, (J)V, null, null, wait, (millis), [153, 153], 60}
+		wait[METHOD_REF]{wait(), Ljava.lang.Object;, (JI)V, null, null, wait, (millis, nanos), [153, 153], 60}
+		""".strip()
+		,
+		requestor.getResults()
+	);
+}
 }
diff --git a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests_1_5.java b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests_1_5.java
index dba444e9cd8..2035e7293bf 100644
--- a/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests_1_5.java
+++ b/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/CompletionTests_1_5.java
@@ -9297,7 +9297,7 @@ public void test0295() throws JavaModelException {
 	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
 
 	assertResults(
-			"compareTo[METHOD_REF]{compareTo(), Ltest.ComparableTest<*>;, (*)I, compareTo, (t), " + (R_DEFAULT + R_RESOLVED + R_INTERESTING + R_CASE + R_NON_STATIC + R_NON_RESTRICTED) + "}",
+			"compareTo[METHOD_REF]{compareTo, Ltest.ComparableTest<*>;, (*)I, compareTo, (t), " + (R_DEFAULT + R_RESOLVED + R_INTERESTING + R_CASE + R_NON_STATIC + R_NON_RESTRICTED) + "}",
 			requestor.getResults());
 }
 //https://bugs.eclipse.org/bugs/show_bug.cgi?id=99928
@@ -14726,20 +14726,20 @@ public void testBug573279() throws Exception {
 	int cursorLocation = str.lastIndexOf(completeBehind) + completeBehind.length();
 	this.workingCopies[0].codeComplete(cursorLocation, requestor, this.wcOwner);
 	int relevance = R_DEFAULT + R_INTERESTING + R_RESOLVED + R_CASE + R_NON_STATIC + R_NON_RESTRICTED;
-	assertEquals("add[METHOD_REF]{add(), LMyArrayList<Ljava.lang.String;>;, (Ljava.lang.String;)Z, null, null, add, (t), replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"clone[METHOD_REF]{clone(), Ljava.lang.Object;, ()Ljava.lang.Object;, null, null, clone, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"equals[METHOD_REF]{equals(), Ljava.lang.Object;, (Ljava.lang.Object;)Z, null, null, equals, (obj), replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"finalize[METHOD_REF]{finalize(), Ljava.lang.Object;, ()V, null, null, finalize, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"getClass[METHOD_REF]{getClass(), Ljava.lang.Object;, ()Ljava.lang.Class<+Ljava.lang.Object;>;, null, null, getClass, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"hashCode[METHOD_REF]{hashCode(), Ljava.lang.Object;, ()I, null, null, hashCode, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"notify[METHOD_REF]{notify(), Ljava.lang.Object;, ()V, null, null, notify, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"notifyAll[METHOD_REF]{notifyAll(), Ljava.lang.Object;, ()V, null, null, notifyAll, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"remove[METHOD_REF]{remove(), LMyArrayList<Ljava.lang.String;>;, (Ljava.lang.Object;)Z, null, null, remove, (o), replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"size[METHOD_REF]{size(), LMyArrayList<Ljava.lang.String;>;, ()I, null, null, size, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"toString[METHOD_REF]{toString(), Ljava.lang.Object;, ()Ljava.lang.String;, null, null, toString, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"wait[METHOD_REF]{wait(), Ljava.lang.Object;, ()V, null, null, wait, null, replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"wait[METHOD_REF]{wait(), Ljava.lang.Object;, (J)V, null, null, wait, (millis), replace[289, 318], token[289, 292], "+relevance+"}\n" +
-			"wait[METHOD_REF]{wait(), Ljava.lang.Object;, (JI)V, null, null, wait, (millis, nanos), replace[289, 318], token[289, 292], "+relevance+"}",
+	assertEquals("add[METHOD_REF]{add, LMyArrayList<Ljava.lang.String;>;, (Ljava.lang.String;)Z, null, null, add, (t), replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"clone[METHOD_REF]{clone, Ljava.lang.Object;, ()Ljava.lang.Object;, null, null, clone, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"equals[METHOD_REF]{equals, Ljava.lang.Object;, (Ljava.lang.Object;)Z, null, null, equals, (obj), replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"finalize[METHOD_REF]{finalize, Ljava.lang.Object;, ()V, null, null, finalize, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"getClass[METHOD_REF]{getClass, Ljava.lang.Object;, ()Ljava.lang.Class<+Ljava.lang.Object;>;, null, null, getClass, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"hashCode[METHOD_REF]{hashCode, Ljava.lang.Object;, ()I, null, null, hashCode, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"notify[METHOD_REF]{notify, Ljava.lang.Object;, ()V, null, null, notify, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"notifyAll[METHOD_REF]{notifyAll, Ljava.lang.Object;, ()V, null, null, notifyAll, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"remove[METHOD_REF]{remove, LMyArrayList<Ljava.lang.String;>;, (Ljava.lang.Object;)Z, null, null, remove, (o), replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"size[METHOD_REF]{size, LMyArrayList<Ljava.lang.String;>;, ()I, null, null, size, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"toString[METHOD_REF]{toString, Ljava.lang.Object;, ()Ljava.lang.String;, null, null, toString, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"wait[METHOD_REF]{wait, Ljava.lang.Object;, ()V, null, null, wait, null, replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"wait[METHOD_REF]{wait, Ljava.lang.Object;, (J)V, null, null, wait, (millis), replace[289, 292], token[289, 292], "+relevance+"}\n" +
+			"wait[METHOD_REF]{wait, Ljava.lang.Object;, (JI)V, null, null, wait, (millis, nanos), replace[289, 292], token[289, 292], "+relevance+"}",
 			requestor.getResults());
 }
 public void testGH969_completeOnFirstArgumentPosition_noToken() throws Exception {
diff --git a/org.eclipse.jdt.core/codeassist/org/eclipse/jdt/internal/codeassist/CompletionEngine.java b/org.eclipse.jdt.core/codeassist/org/eclipse/jdt/internal/codeassist/CompletionEngine.java
index 9d1e9580d72..1f15e77275d 100644
--- a/org.eclipse.jdt.core/codeassist/org/eclipse/jdt/internal/codeassist/CompletionEngine.java
+++ b/org.eclipse.jdt.core/codeassist/org/eclipse/jdt/internal/codeassist/CompletionEngine.java
@@ -3269,8 +3269,16 @@ private void completionOnMessageSendName(ASTNode astNode, Binding qualifiedBindi
 			CompletionOnMessageSendName messageSend = (CompletionOnMessageSendName) astNode;
 
 			setTokenRange(messageSend.sourceStart, messageSend.sourceEnd);
-			if (messageSend.statementEnd > messageSend.sourceStart)
-				setSourceRange(messageSend.sourceStart, messageSend.statementEnd);
+
+			if (messageSend.statementEnd > messageSend.sourceStart) {
+				// we ensure any existing arguments are preserved
+				boolean existingMethodCallHasBeenProvidedArguments = (messageSend.arguments != null);
+				if (existingMethodCallHasBeenProvidedArguments) {
+					setSourceRange(messageSend.sourceStart, messageSend.sourceEnd);
+				} else {
+					setSourceRange(messageSend.sourceStart, messageSend.statementEnd);
+				}
+			}
 
 			this.completionToken = messageSend.selector;
 
@@ -3586,7 +3594,33 @@ private void completionOnQualifiedNameReference(ASTNode astNode, ASTNode enclosi
 	private void internalCompletionOnQualifiedReference(ASTNode ref, ASTNode enclosingNode, Binding qualifiedBinding, Scope scope,
 			boolean insideTypeAnnotation, boolean isInsideAnnotationAttribute, InvocationSite site, char[][] tokens, long[] sourcePositions)
 	{
-		long completionPosition = sourcePositions[sourcePositions.length - 1];
+		// we take the cursor location into consideration regarding segments of a qualified name,
+		//
+		// Example:
+		// void x(TreeNode node) {
+		//   TreeNode other = node.ch|.child.child.parent;
+		//   // ...
+		// }
+		//
+		// in the above example, completionPosition will match against the cursor after 'ch', i.e. sourcePositions[1].
+		// (sourcePositions[0] points to 'node', sourcePositions[4] to 'parent')
+		long completionPosition = sourcePositions[sourcePositions.length - 1]; // use last segment as a fallback for resilience
+		for (long p : sourcePositions) {
+			int start = (int) (p >>> 32);
+			int end = (int) (p);
+			if (start > end) { // in specific cases like "node.|.child" the start might be larger than the end (see GH-2620)
+				// swap them for sanity / resilience
+				int tmp = start;
+				start = end;
+				end = tmp;
+			}
+			boolean cursorWithinBounds = (start <= this.actualCompletionPosition && this.actualCompletionPosition <= end);
+			if (cursorWithinBounds) {
+				completionPosition = p;
+				break;
+			}
+		}
+
 		if (qualifiedBinding.problemId() == ProblemReasons.NotFound) {
 			setSourceAndTokenRange((int) (completionPosition >>> 32), (int) completionPosition);
 			// complete field members with missing fields type