OSX hidden tab task switch crash.

When attempting to switch out of a QT application while the contents of a hidden tab are being shown will cause the program to crash with an exception type of EXC_BAD_ACCESS. See the attached application and crash dump.

This only seems to affect OSX as my coworker was unable to reproduce this in Windows.

Steps to reproduce:

1. Open the attached application.
2. Click the button to show the hidden tab.
3. Switch to another program by any means. (I clicked on another, unrelated window.)

Results:

Program crashes. (See attached.)

Expect:

Nothing happens.