Activity pane consistency issues

[wesm]

A couple issue issues:

• If you open the detail pane on the activity page, navigate to an issue (e.g. by clicking a link), then press the back button, the detail pane will be closed on return
• If you press Escape while the PR Merge modal is open, it closes not only the modal but also the detail pane

[mariusvniekerk]

clanking, this is also true for the PR list when navigating there from the workspaces