To regain the old toolbar features, you need to edit stdtoolbars.ui and install
associated icons. If you have an old 1.4.1 or 1.4.2 installation, you can find
the old toolbars in LYXDIR/Resources/ui, and the icons in
LYXDIR/Resources/images as .xpm files.
The toolbar feature I wanted back was the Export PDF, which is in stdtoolbars.ui
as this line:
Item "Export PDF (pdflatex)" "buffer-export pdf2"
The corresponding icon is called buffer-export_pdf2.xpm.
The 1.4.3 installer caused a problem for me, because it does not include the old
windefault.ui and wintoolbars.ui. But my old installation did use those .ui
files, and Lyx would quit, complaining that windefault.ui does not exist. It
would be better if that error still allowed the program to run, defaulting to
default.ui. Instead, I had to dig up the old windefault.ui (luckily I still had
my 1.4.2 directory) and copy it to 1.4.3, then start up Lyx, then change the ui
to default.ui, then delete the no-longer-needed windefault.ui. Kind of a pain.
Plus the PDF button was handy.
