Changing or resetting the Space shortcut removes it from other commands that share it (Trigger, Play/Stop, Stop Record)

Bug description

In Audacity 4.0, several transport commands ship with the same default shortcut — Space (e.g. Trigger, Play/Stop, and Stop Record). The Keyboard Shortcuts preferences do not section/group commands that share the same key, and they are not treated as a group when edited:

1. Reassigning the Space binding on one command removes Space from the other commands that originally used it — one at a time (from Trigger, to Play/Stop, to Stop Record).
2. Pressing "Reset to Default" on any command that uses Space removes the Space binding from the other commands that use it.

Steps to reproduce

1. Open Preferences > Keyboard Shortcuts.
2. Locate the commands that share the Space shortcut (Trigger, Play/Stop, Stop Record).
3. Change the Space binding on one of them to a different key.
4. Observe that Space is removed from the other commands one by one.
5. Click "Reset to Default" on any command that uses Space.
6. Observe that the Space binding is also removed from the other commands.

Expected behavior

• Commands that share the same default shortcut are sectioned/grouped (or at least treated as a unit) so that editing or resetting one does not silently strip the binding from the others.
• "Reset to Default" on a command restores that command's default without deleting the default shortcut from other commands that share it.

Actual behavior

• Reassigning the key on one command removes Space from sibling commands one at a time (Trigger, then Play/Stop, then Stop Record).
• "Reset to Default" removes the Space shortcut from the other commands that use it.

Audacity Version

Audacity 4.0.0

Operating system

Windows

Additional context

The affected defaults appear to be the transport commands that share Space by default.