Cannot delete last atom by selection

[mquevill]

Avogadro version: 1.94.0-21-g0942bdb

• Avogadrolibs: 1.94.0-103-g91db7e7
• Qt: 5.12.8

Desktop version:

• OS & Version: Linux Mint 20.2 (based on Ubuntu 20.04)
• Compiler: gcc 9.3.0

Describe the bug
Selecting atoms and deleting (by pressing "delete"), works much better due to #672 and #677. However, it still leaves the last atom if it's the only one. When deleting part of a molecule, it works as expected.

To Reproduce
Select all atoms and tap "delete". One atom will be remaining and must be deleted by unselecting and pressing "delete". Even if the setup starts with only one atom, it can never be deleted by this method.

Expected behavior
All selected atoms would be deleted.

Screenshots
All atoms selected:

After pressing "delete":

[MSoegtropIMC]

I can confirm this - it seems to be the first atom (#1) btw. which cannot be deleted. Even when there are multiple atoms, one cannot delete atom #1 by selection. One can delete it with edit / right click, though.