KDE Failed Keyboard Shortcut
KDE 5 has become the primary desktop environment in the house network. Part of enhancing the environment is configuring keyboard shortcuts.
Mostly this is a non event except a keyboard shortcut to launch the Trinity Desktop Environment (TDE) KMail from within KDE always failed. Searching the web finds several KDE bug reports about failing keyboard shortcuts. One possible clue in those reports is KDE keyboard shortcuts seem to fail more often when launching non KDE software. The solution seems to be not using the standard
Shortcuts dialog and instead use the
Custom Shortcuts dialog.
That did indeed help resolve TDE KMail not launching with a custom shortcut.