wxGUI: force height for colour widget (wxPython 3 fix)

       (merge https://trac.osgeo.org/grass/changeset/64167 from trunk)


git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@64168 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/gui_core/forms.py

@@ -1479,7 +1479,7 @@ class CmdPanel(wx.Panel):
 
                     btn_colour = csel.ColourSelect(parent = which_panel, id = wx.ID_ANY,
                                                    label = label_color, colour = default_color,
-                                                   pos = wx.DefaultPosition, size = (colorSize,-1))
+                                                   pos = wx.DefaultPosition, size = (colorSize, 32))
                     this_sizer.Add(item = btn_colour, proportion = 0,
                                    flag = wx.ADJUST_MINSIZE | wx.BOTTOM | wx.LEFT, border = 5)
                     btn_colour.Bind(csel.EVT_COLOURSELECT,  self.OnColorChange)