How to prevent UI updates interfering with user's actions?

[Carsten A. Arnholm]

Fabian Cenedese wrote:
>> I agree that in general one should not update the controls the user
>> is working on (and we might allow such updates to be switched off).
>> On the other hand  it will also be very confusing since the camera
>> itself changes its properties (as it does in auto exposure mode and
>> on some other occasions) without reflecting those changes in the GUI.
>
> The user won't drag forever. So you could just set a modified flag to
> know after release that you need to adjust the GUI to the changes
> from other places.

Hi,

This would prevent updates reflecting "spontaneous changes". The camera has 
some physical connections that could cause the properties to change without 
the user doing anything in the GUI first.

But I have now implemented update blocking using the events 
EVT_COMMAND_SCROLL_THUMBTRACK  and EVT_COMMAND_SCROLL_THUMBRELEASE as 
suggested by Vadim Zeitlin. This appears to solve the problem very well, the 
GUI doesn't fight the user updates anymore, and "spontaneous changes" are 
also quite well reflected.

Thanks for the helpful suggestions...!

Regards
Carsten A. Arnholm
http://arnholm.org/
N59.776 E10.457