Every time I try to add a mapwidget to the layout, or open an existing layout, change it - for example, the size of any element, and if there is a mapwidget there - the workbench crashes with an error.

The same story, if you work with a font - when you select it in the list of files - the workbench crashes.

This problem has been around since 1.26

1. Create a new layout

2. place the mapwidget there, adjust the element's size (and apply the changes via Enter) - you'll most likely crash at this stage.

3. Or, open an existing layout that already contains the mapwidget, change the size of any element (and apply the changes via Enter) - you'll most likely crash as well.