adding apps to the multiwindow bar
I've looked through the thread and this variant of the "how to add apps to the multiwindow bar" question doesn't seem to have come up.
I noticed a few apps seemed to have added themselves to the multiwindow bar, without intervention from me. Very handy they were too (in particular Dashlane - brilliant having that as a multiwindow app)
However they have now removed themselves from the sidebar; Dashlane removal was probably due an update in the Dashlane app
How do I get them back on the multiwindow bar?