### Steps to reproduce

Begin of the deletion _Please write down the steps to reproduce. Try to write down all necessary preconditions (what permissions do you have, are other users involved?). Example:_

End of the deletion 1. Create assignee (or any other) board
2. Add at least one column
3. Create a Begin of the insertionsub-projectEnd of the insertion Begin of the deletion subprojectEnd of the deletion "To be removed"
4. Add a "including Begin of the insertionsub-project"End of the insertion Begin of the deletion subproject"End of the deletion filter with "To be removed" selected
5. Delete the Begin of the insertionsub-projectEnd of the insertion Begin of the deletion subprojectEnd of the deletion
6. Open the board

### What is the buggy behavior?

Begin of the deletion _Please describe the bug in as much detail as possible. Example:_

End of the deletion * All columns are gone
* Little info icon is shown on the left side
* No errors are shown

### What is the expected behavior?

Begin of the deletion _Describe how the application should behave like. Example:_

End of the deletion * Boards remain OR
* Error is Begin of the insertionnoticeableEnd of the insertion Begin of the deletion noticableEnd of the deletion

###