Extra item shows up in the schema collection. Pretty simple, although a pain to track down: just an off-by-one in a string copy, so simpleSchema.xsd becomes simpleSchema.xs. Other code references the schema, which isn't found by the original name so another entry is created with the right name.
Undead toolbars. Create a new custom toolbar, restart, delete the toolbar, restart, it's baack! Little trickier: turns out every "main window" clones the toolbar, and on delete one wasn't getting removed—the one in the VBA window (I was distracted by a comment that claimed otherwise).
Incorrect correction. On Japanese Word, when \alpha is autocorrected to α, the "stop autocorrecting" item on the "on object" floating menu was always checked. Turns out that in Japanese, sometimes backslash and the Yen sign are equivalent, sometimes not. When you type \ it displays as ¥ but still acts as a backslash for autocorrection. However, we fetch the display text, not the document text. When we populate the floating menu, we check if there's an autocorrect item for ¥alpha, and when there isn't, we assume the user has turned off autocorrection for it. Fix was to temporarily turn off the "convert backslash to yen" flag when formatting text for the autocorrect lexer, although this still needs to be examined to see if we always want to convert in this case.
Another set of settings. Creating another Word application and toggling an option fails. Turns out it crashes the other Word because the application was created without a window, and somebody was assuming we had one. Only tough because it required debugging another instance and because someone threw a spanner into the gears of my finely-tuned debugging environment (remember those remote tests I was trying to pass earlier? the Office test framework guys like to stomp all over everything and not clean up after themselves).