[Lazarus] Crash in CalendarPopupForm

[Bart]

Hi,

I just noticed a crash in TCalendarPopupForm.
It happens under Windows only.

When you pop-up the form, then press Alt-key, the form disappears (a
bit unexpectedly).
Any key or mouse click or keystroke after that will kill the appication with a
crash in the windowproc (see backtrace included in the attachement).

I broke it down to a minimal testcase (just created a skeleton of the
popup form), which is attached to this mail.

Is there some fault in the WindowProc, or is this a design fault (and
if so, how to fix that)?

I included a workaround: start the program with parameter --fix , and
the crash will not occurr.

The purpose of this all is that the form shall be hidden and freed as
soon as it loses focus. This happens without crash if you remove the
focus by any other means then pressing Alt-key.

Bart
-------------- next part --------------
A non-text attachment was scrubbed...
Name: pop.zip
Type: application/zip
Size: 5087 bytes
Desc: not available
URL: <http://lists.lazarus-ide.org/pipermail/lazarus/attachments/20150714/3c791520/attachment-0002.zip>