How to apply ColorpickerDlg in TGEA

In TGE, we can use the ColorpickerDlg to chose color. But TGEA seems not support this feature. I noticed that there indeed is a ColorPickerDlg.gui in common\ui directory, and in canvas.cs I found this script:
....
exec("~/ui/ConsoleDlg.gui");
//exec("~/ui/ColorPickerDlg.gui");
exec("~/ui/MessageBoxOkDlg.gui");
exec("~/ui/MessageBoxYesNoDlg.gui");
exec("~/ui/MessageBoxOKCancelDlg.gui");
exec("~/ui/MessagePopupDlg.gui");
exec("~/ui/HelpDlg.gui");
exec("~/ui/RecordingsDlg.gui");
....
I tried to reactivate the "exec("~/ui/ColorPickerDlg.gui");", however, I got no effect.
I think I must missed something , so anyone would be kindly to help me. Thanks.