Bug 420706

SUMMARY
Columns manipulation by dragging them leads to weird behaviour, they disappear from main window. But they still exist in project explorer, and their order is just as expected. If you try to delete any column now, the program will crash. You may avoid crashing, if you close the spreadsheet, and the reopen it from the Project explorer - everything will look just ok. 

STEPS TO REPRODUCE
1. Create empty project, then add worksheet to it.
2. Drag any column to the left or to the right, you may expect them to swap, but instead one column disappears.
3.  Now trying to delete any column causes a crash

OBSERVED RESULT
Columns are not displayed, program crashes

EXPECTED RESULT
Columns swapped

SOFTWARE/OS VERSIONS
Windows: 7 SP1 x86_64
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 5.63.0
Qt Version: 5.13.1 (собрана с версией 5.13.1)

ADDITIONAL INFORMATION