When detecting the properties of a window, now it shows and lets the user select the window complete class.
When this property is selected in the overlay, `Window class` takes the whole class value, and the option `Match window whole class` is set.
This was not a bug itself, but a known regression from the old kcm which offered this feature.
As such, and introducing a new i18n string, I don't know wether it should be included in 5.19 or 5.20 release.
BUG: 421542
FIXED-IN: 5.??