Thanks, @Lanco_Support-Team.
I upgraded to 3.6.6, but something is odd when I try to italicize text in the excerpt field.
If I select Format > Font > Italic from the menu bar, or Font > Italic from the right-click menu, the text is italicized as expected. However, as soon as I leave the note and move to another one, it reverts back to normal text, with no emphasis. The change doesn’t stick.