Not reopening multiple tabs on launch

Until earlier this spring I was able to quit OmniOutliner with 4 regularly used tabs open and they’d reopen when I relaunched the app.

That no longer happens, and I just get a new, blank outline when I launch the app. And then I have to find and load the outlines.

Is this expected behavior now? Or did I accidentally change a Prefs setting?

(recent Intel iMac, latest Big Sur, latest version of OO)