PLECS uses a web engine to display the help pages. By default, the engine uses a software renderer bundled with PLECS. However, we have observed cases where it does not work properly. For this reason, as of PLECS 4.2, we have added an option to enable hardware-assisted rendering based on the OpenGL/DirectX libraries installed on the user computer.
To switch from software- to hardware-assisted rendering, please open the “PLECS Preferences” dialog in the “File” menu and deselect the checkbox “Use software rendering” in the “OpenGL” preference. After restarting PLECS, the help viewer should work again.