Well I think this is a matter of the window itself and not of a specific code...
Anyway this is what happens:
I draw a rectangular with a given color, and the cursor vanishes below.
I tried to change the color.alpha to 200 and then the cursor is visible again, but very dimy. So there must happen that the window first draws the Rect containing the cursor, and then applies the other colored Rect.
I wondered, is there a way to rewrite the cursor above them (such as redeclaring it) instead of modifying the transparency of the colors?
CODE
this is the command I call:
self.contents.fill_rect(rect,@Colors[color_index])
[....]
and this is the update_cursor:
def update_cursor_rect
x = @D*(@RW+self.index%@bitmap.width)-self.ox
y = @D*(@DW+self.index/@bitmap.width)-self.oy
self.cursor_rect.set(x, y, @D, @D)
end