Firefox has "Open previous windows and tabs" ticked in Settings. I had to force restart MacOS, and upon starting Firefox again my existing windows are invisible. They are shown in the Window menu and when right-clicking the Firefox icon in the MacOS dock, however when I select one of the windows it does not become visible. Command+` does not show the windows either. I can however open new windows. I tried renaming xulstore.json [https://support.mozilla.org/en-US/questions/1131091 per this old article] with no effect. How can I make the existing windows visible again?