Reset your LW configs, looks like something did a number on Modeler's config. Either that, or one heck of a driver problem occurring, but first worth renaming-and-moving existing config, then allowing LW to regenerate new configs, reinstall plugins, etc.
LW2015.3UB on MacPro(12C/24T/10.12.2),32GB RAM, NV 980ti
ALT-F2 in Modeler will hide / restore the main menu. Perhaps you accidentally pressed it.
RE: the white boxes, I get these if I try to run Modeler through Remote Desktop Connection rather than with a direct video link to the monitor via HDMI.
Issue solved. I inadvertently turned off my tool bar, keyboard shortcut :d: unclicked "hide toolbar"
Coincidentally, After effects had an issue that forced me to upgrade my video drivers, and Viola, situation resolved.
Again, Thanks for your help. You guys ROCK !