A new version of GNU Octave has just been released (version number 4.2) which unfortunately contains a few GUI related regression bugs. Firstly, the menu options such as File, Options, Grid etc. are hidden. A temporary fix is to replace the featool.m launch script file with the one in the following link
Alternatively, Octave versions 4.0.0 through 4.0.3 can still be used as few new Octave features will improve FEATool functionality.
The second bug concerns Windows systems with HiDpi screens. In this case be aware that radiobuttons and checkboxes will be very small if not tiny. Unfortunately there is currently no fix for this except for using an older version of Octave.
Please do report if you discover any other anomalies while using FEATool with Octave 4.2