On Windows 8 Pro 64-bit, many of the secondary dialog boxes (i.e., when something needs to be selected) appear behind the Preferences window and cannot be interacted with. You can sort of get around this issue by moving the preferences window to the side then initiating the secondary dialog again (it renders in the center of the screen), but that is suboptimal. As an example to reproduce this issue: Define a new button to correspond to a user-generated action. Click on icon to customize the button for the action. It looks like nothing happens, but in reality the icon selection window has actually popped up in the background behind the main Preferences window. Icon selection window appears in the jump list on the desktop taskbar but even after selection in the jumplist it cannot be interacted with at all.
This sounds very similar to these two bugs filed in the ubuntu bugtracker: https://bugs.launchpad.net/ubuntu/+source/claws-mail/+bug/921973 https://bugs.launchpad.net/ubuntu/+source/claws-mail/+bug/802673 I've been experiencing something similar to this since a year ago or so when I upgraded to 3.9.0 and now with 3.9.1 from the claws-mail team PPA. Both set of steps from ubuntu bug 921973 will reliably reproduce the problem on my system. Anyone have ideas what might be causing this strange behavior?
*** This bug has been marked as a duplicate of bug 2866 ***