Link Windows and Crosshairs Issue

[shakes76]

If one enables "Link Windows" and then click the "Crosshairs" button, only first window has their crosshairs enabled. Consequently, clicking middle mouse to show crosshair in other windows causes crash.

The crash needs to be fixed and the crosshair enabling needs to be applied properly when link windows is enabled first.

[shakes76]

Fixed the crash in commit 3f5995a
The crosshair enabling bug still exists.