Icon "edit-undo" may not exist - use an icon from CMake instead.
Fix a crash with item.properties.keys(). Apparently, QMap::keys() returns a new list since Qt 6 [1][2], so item.properties.keys().begin(), item.properties.keys().end() is no longer a valid range.
item.properties.keys(). Apparently,QMap::keys()returns a new list since Qt 6 [1][2], soitem.properties.keys().begin(),item.properties.keys().end()is no longer a valid range.[1] https://doc.qt.io/qt-6.2/qmap.html [2] https://doc.qt.io/qt-5/qmap.html
Ideally, tests are run on GitHub CI, but I don't have time to do that for now.