In opposite to TGVerticalLayout and TGHorizontalLayout, TGMatrixLayout
does not take into account the border width of the parent frame.
This causes it to look very bad when used with TGGroupFrame (The title of
the Frame is overlapped by the matrix)
In TGMatrixLayout::Layout, I would just suggest to change
Int_t x = fSep, y = fSep;
by
Int_t bw = fMain->GetBorderWidth();
Int_t x = fSep + bw, y = fSep + bw;
I made a derived class with this modification, and it looks much better.
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Mathieu de Naurois
LPNHE Ecole Polytechnique
denauroi@polhp1.in2p3.fr