wx.lib.splitter.MultiSplitterWindow SetMinimumPaneSize() doesn't work as intended

[AlessandroMattiazzi]

The function SetMinimumPaneSize() is working only on the first window, while the second can be resized smaller the minimum pane size, I think this is not the correct behaviour since the description reads as follow:

"""
Set the smallest size that any pane will be allowed to be
resized to.

param int `minSize`: the minimum size of pane

"""

This is actually an accurate description of what the same function in wx.SplitterWindow does.

Another problem with SetMinimumPaneSize() is that the window isn't automatically resized to the smallest size if its current size is smaller than the minimum, but a workaround can be applied with self.split.SetSashPosition(pane_idx, split_position).

Also it would be nice to clarify how the idx for each window is defined and where, maybe even let the user decide the number