"Would you like to try our improved style?" window opens with the last tab.
Using latest nightly OS: Windows 10 (10.0), Arch.: x86_64, MuseScore version (64-bit): 220.127.116.115183078, revision: 905e64b
I previously closed the program with a couple of 3.5.x scores after not accepting the "improved style." When I opened 3.6 the "...improved style" dialog box opened with the final tab for each 3.5.x score that opened with it. What has happened in the past is that this window opened when you switched to the score's tab so you would know which score the dialog was asking about.
To be clear. I had two 3.5.2 scores opened in the last session and two 3.6 score. I closed and reopened the program and the "...improved style" dialog opened twice with the last score that opened, which happened to be a 3.6 score. Since this is an update to the RC I would consider it a blocker since the final 3.6 version cannot be released with this bug.