TSpeedButtons in Groupboxes

[MSABC]

Hi all,

under Windows Vista I have a behaviour I don't understand:

My main formular has a TPaintBox inside a TScrollBox. => So far OK
Around are some TSpeedButtons, some in groupboxes, some without. => So far OK
With some commands I open a (Sub-) formular to edit some drwaing parameters. => So far OK

After closing this sub-formular the TSpeedButtons inside the groupboxes don't show any reaction.
It seems that the call-back routines are not called.
The TSpeedButtons without groupboxes behave as desired.
After one (void) click inside the TPaintBox, the grouped TSpeedButtons seem to be re-activated.
=> That's not OK.

If I delete all groupboxes (putting the buttons on the main formular) the behaviour is OK,
but the GUI design lacks structure.

Is there any known reason why TSpeedButtons inside groupboxes temporarely loose activation?



 - MS-Windows, 32bit,
 - Lazarus 1.42
 - FPC 2.6.4

regards

M. Schäfer