Hello

I tried the new source and the display problem are gone. Good work!
But there are still few changes that are necessary to get it compiled  
on my machine.

These lines are ambiguous:
src/DlgSimrCfg.cpp:41
src/gnucap/DlgGenCfg.cpp:34
src/ngspice/DlgSrcCfg.cpp:34

I fixed it by changing the wxDialog function to:

wxDialog( poWin, -1, wxT(""), wxDefaultPosition, wxDefaultSize,  
wxDEFAULT_DIALOG_STYLE, wxDialogNameStr )

src/Makefile:94 needs a space between -o and $(BINDIR):

$(CC) -pipe -o $(BINDIR)/$(PROG) obj/*.o $(LIB)

For making Mac OS X usable app I added this rule to the main Makefile:

macapp : Info.plist bin/gspiceui GSpiceUI.icns
     -mkdir GSpiceUI.app
     -mkdir GSpiceUI.app/Contents
     -mkdir GSpiceUI.app/Contents/MacOS
     -mkdir GSpiceUI.app/Contents/Resources
     cp Info.plist GSpiceUI.app/Contents/
     echo -n 'APPL????' > GSpiceUI.app/Contents/PkgInfo
     cp bin/gspiceui GSpiceUI.app/Contents/MacOS/gspiceui
     cp GSpiceUI.icns GSpiceUI.app/Contents/Resources/

You'll need the two attached files. Info.plist is xml and contains  
the version, the executable name and some other info. It only  
contains the "necessary" you can change it the way you think it  
should be.
GSpiceUI.icns is the suitable Icon I converted from the one you made.

Would be cool if you could perform these changes on your source. I'll  
further test your app and report any issues. If you got any Mac  
related questions I'm happy the help.

Cheers,
Ezra.