Strange Firefox crash using Scan Popup

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I've enabled scan popup functionality and set it to show only when Ctrl+Alt are pressed. but I noticed sometimes it stops working, while the Ctrl+C+C Hotkey still works.

I think this is how the crash happened...
Last time Ctrl+Alt Scan Popup stopped working I quit GoldenDict and opened it again. Then to test it, hovered over the "Embed" button in a Youtube video while holding Ctrl+Alt, and Firefox crashed immediately! I could not reproduce it again.

From Firefox Crash Report: (If you need the full Firefox Crash Report let me know to whom can I PM the link.)

CPU: x86
CPU Info: GenuineIntel family 6 model 28 stepping 2
Crash Reason: EXCEPTION_ACCESS_VIOLATION_EXEC

GoldenDict v1.0.1
Firefox v3.6.13
Windows XP Pro SP3 with all the latest security updates