Re: [MACTCL] Minor bug in Tck/Tk 8.5.17: hidden widgets flicker on <Expose>

[Russell O. <ro...@uw...>]

On 12/15/14 8:12 PM, Michiel de Hoon wrote:
> Hi Russell,
>
> Can you provide a test script that demonstrates the flickering of hidden widgets?
> This would help to establish what the exact cause of this behavior is.
>
> Thanks,
> -Michiel.
>
>> I have a log window consisting of a Text widget, scroll bar, and various
>> widgets to control the display. Some of of the control widgets are
>> usually hidden, using grid.remove() to remove the parent frame of the
>> widgets.
>>
>> With Tcl/Tk 8.5.17 on MacOS we see the hidden widgets briefly appear
>> whenever the main frame for this window receives an <Expose> event.
>> Unfortunately such an event occurs whenever a new item is appended to
>> the log (I'm not sure why). New lines can come in quite often, leading
>> to an annoying flicker of the hidden widgets.
>>
>> Clearly this is merely a cosmetic annoyance. Nonetheless, I'm reporting
>> it and asking if anyone can suggest a reasonable workaround. The only
>> one I've thought of, so far, is to hide widgets using grid.forget
>> instead of grid.remove (I have not verified that works, but I'd be
>> amazed if it didn't). That's a bit of a nuisance because I'll have to
>> record the grid parameters, but it's certainly doable. If anyone has a
>> better idea I'd love to hear it.

I'll have a go when I get some free time, but I suspect we'll have to 
live with it in any case. It sounds like a side effect of cleaning out 
the reliance on undocumented Apple calls.

-- Russell