When using iwidgets::panedwindow I couldn't get rid of the margins between the panes and the sashes (shown in blue arrows in the small picture). Is there a way to get rid of them, so that the pane will be next to the sash, like in ttk::panedwindow?
A picture of a form using iwidgit::panedwindow:

A close picture of the "problem":

A picture of (almost) the same form using ttk::panedwindow:
