@itziakos That's not quite sufficient, because the user could set the `bgcolor` to a 3-tuple with no alpha.  Even if there is an alpha value, we probably don't want to compare it in this case.  Using `if self.bgcolor_[:3] == color_table[grid_color][:3]:` works, but IMO is not as clean as using the `colors_equal` function.

We probably want something like `colors_almost_equal` as well, because it could be set to a color indistinguishable by eye.  I think that's overkill in this case, though.  In fact, I am tempted to take out this check altogether and let the user be responsible for grid color.  A simple check here does no harm, though, I suppose.