Color Gradient editor: 'Position' spinbox is difficult to use

[jankrassnigg]

In the color gradient asset, there is a spinbox to change the 'Position' of a keyframe. Trying to change the value by using 'Delete' or 'Backspace' and typing a value, is quite tricky, as certain keys will remove the value, but then fill up the spinbox with 0.00, which you then cannot edit, and you first have to remove a 0 again.

Maybe we can use the ezQtDoubleSpinBox instead.