ColorDialog don't resize correctly on small screens

The SaturationLightnessPicker control is set to always have a square
shape but in this way when the screen height is not sufficient
(as in the case of smartphones) the dialog does not fit going
beyond the edges of the screen and became unusable. In attach two screenshots, one where the dialog fill all the screen but is usable and the second where the height is not enough and the dialog was drawed incorrectly.