[Bug/Feature Request] KComboBox's should follow the DatTimePicker layout(s)

[Smurf-IV]

The drop-down on the Date Picker stretches but the Combo Box does not, should it not be the same?
NumberUpDown & Combo Box maintain the drop-down height with a constant gap
I would like them all to stretch, but would accept them being fixed height, but consistent through all control types

( I also note that text does not consistently place itself, some are centres some are positioned at the top of the control )

To my mind, the way Date Pickers behave seems correct, stretch & centre

Originally posted by @MattH-Work in #1636 (comment)