Welcome to TVPaint Community forums !

I tried to use a Mixer of a Color Picker as sub palette(I will import my images) , but I couldn't.
I can't control a Mixer window size.
The window size is restricted to too small.
I want to resize a Mixer window of a Color Picker.
I don't know what to do.
Please tell me how to solve this problem.

You can't enlarge the color mixer. You can only make it longer.

Put your cursor at the bootom of the color mixer => a double arrow will appear => Click and make your color mixer longer.

the dimensions (in pixels) of colormixer images are:
172 X height of your monitor ( )

having a wider or even multiple mixers would indeed make a nice feature request

me too ^^;