slow refresh with tkcalendar

[claudiodriussi]

Hi Alejandro, First of all thanks for your work.

I found a issue using tkcalendar DateEntry, but I think the same can happen even with other components

If I add a DateEntry in the designer all workflow slow down and it can be really impossible do something like change the id of widgets.

I think this is because the refresh of the component is very slow so the event loop almost crashes.

I suggest to add a button to freeze the refresh on the Preview panel so we can work on components quickly ad update the preview only when needed.

I tried it in a PC with OS Ubuntu 22.04, 16GB ram, Intel I7.

Many thanks.