After I applied the WannaCry patch (32-bit Win7SP1), the focus in Windows Explorer has been following the mouse. I hate to fall prey to the "Post hoc" fallacy, but that patch is the only thing I can think of that I've changed in ages on this PC. Now, whenever the pointer hovers more than very briefly over any item in Windows Explorer, it 'selects' that item in the same fashion it used to from a single click. So then a single-click registers as a double-click.
If I hold the key and move the pointer fairly slowly, it selects every item the cursor passes over. If I hold the key, hover over any menu item (it is selected), then slide the pointer quickly to any other menu item and hover there, the first and last and all in between are selected.
If I double-click on a folder, the second click is buffered and passed on to whatever menu item lies directly underneath the folder I clicked on. So if the file underneath has any function associated with it (open or run), that function also executes.
So it's treating a hover exactly the same as a single-click.
I triple-checked and what I have configured in "Folder Options" is the same as it always was, "Double-click to open an item (single-click to select)". Under other circumstances I would select the single-click option, then switch back, just to test the results, but I can't because the single-click option is grayed-out, unavailable.
Focus elsewhere, such as when changing windows, in unaffected. Changing the active window still requires a single-click and does NOT follow the cursor. The only place thus far I have noted this behavior is in Windows Explorer.
Neither my (ESET) antivirus nor Malwarebytes find any irregularities.
My next step is to use Windows Restore (which I'm pretty confident will fix the problem) but I'm posting here in the hope I can find the cause and make this a learning experience, before I invoke the M$ time machine.
