Just happened again on Inkscape, fully patched Xenial. Opened file, the menus were there. Closed Inkscape, reopened it two minutes later, the menus are gone and stayed gone until re-login.
Just happened again on Inkscape, fully patched Xenial. Opened file, the menus were there. Closed Inkscape, reopened it two minutes later, the menus are gone and stayed gone until re-login.