Ok, how about this for the commit message
Changes to wxSmith code generation:
Stop SetSizeHints() being used for every window containing a sizer. The wxWidgets documentation recommends SetSizeHints to only be used on top level windows
https://docs.wxwidgets.org/3.0/classwx_sizer.html#abc460cd0e2bb3bde72142fdb434bc546Added 'Lay out window' option for top level windows. If enabled (the default) the wxWidgets layout sytem is called and the window size is set using SetSizeHints(), Fit() or Layout() as appropriate. If disabled no calls are made to the layout system, allowing extra controls to be added/removed outside of wxSmith managed code. Note: after adding,removing or hiding controls you need to call SetSizeHints, Fit() or Layout().
I'm not sure if the tool tip should be much longer. IMHO tool tips should be fairly short. It's likely that this function is only of much use to people who have a reasonable understanding of how windows are laid out. In that case the tip is probably enough as it is.
By the way are you adding tips for all of the other options?