[asleyam]

I went through those steps several times in Mohave 10.14.6 with sigil 0.9.18 and did not have that issue. No save as pop up dialog box after sigil window closed and another epub opened. The steps included keeping dialog box on top, as well as behind other windows and apps. I use a trackpad with the iMac to control backing and forwarding of windows, as well as using several desktops. I tried various permutations and still not been able to recreate that issue. Very odd.

I did some further testing with 0.9.991 in an external ssd mohave clone, an external ssd Catalina installation, in a 2013 retina MacBook Pro (tried them all both in dark and light mode, with and without my qt styles pref files) and still could not recreate the save as persistent save as problem.