Meowrs
After finally getting 9.0 set up to a usable state, I went out into the world to test out my characters’ new ability loadouts and found that I was having issues with tab targeting, especially with Target Nearest/Previous Enemy keybinds (they’re assigned to my mousewheel up/down respectively).
At first I thought an addon might be doing this so I moved the AddOns folder out to the desktop so no addons were present to load since I know that even “disabled” addons still load and cause issues. No dice. I still couldn’t properly cycle through mobs while attacking (in combat).
After much testing at the training dummies in Stormwind (so I didn’t get killed during said testing) I’ve discovered that the base ui buttons are causing tab targeting functions to become blocked if the mouse cursor is behind (over) any of them. This includes action bar buttons, the action bar switching buttons, the mini-bar buttons, and all of the bag buttons/icons. Basically any part of the baseline UI that is clickable (i.e. a button of one type or another) is preventing target cycling from working.
I can get into combat and I can tab target and use my mousewheel to cycle through targets freely if my cursor is anywhere except when over a baseline UI button.
I’m unsure what’s causing this, but when I investigated further, I ran into this inside BugGrabber:
98x Couldn't find inherited node: StatusBar
This was checked with only BugGrabber and its required dependencies installed. No addon was listed in the window, just that one line, indicating it’s an issue with the base UI that started occuring with the 9.0 prepatch release.
This is on the Mac client, and occurs whether or not I’m using the new hidden ExclusiveWindowMode CVAR to maintain app focus lock (required for the software I use to control the mouse curves). And as a final test, I temporarily disabled that software and still had the problem (and a mouse too slow to play with!).
This is extremely debilitating for anyone like myself that has to click abilities for one reason or another.
Edit: Another player confirmed the base UI buttons are interfering with mouse interactions. Basically keyboard input is not blocked, but mouse interactions like the scroll wheel are blocked when the cursor is over a UI button.