So yes, using mousewheel in properties window scrolls explorer as well
Don’t know exactly for how long this has been happening, 1-2 days im guessing.
I’m running Windows 10 Pro 64-bit
This happened to me the other day but went away… Weird… 
This was happening to me last week, only with the script editor instead of the properties window.
Happened to me a few weeks ago. I just had to scroll somewhere with my mouse over the studio window for the explorer to also scroll. I tried closing the place (not studio), enabling/disabling the explorer and other things, … but in the end the only “fix” was restarting studio.
That’s cool! 
Can this be fixed please? I’ve been dealing with this bug ~5 times a day for the past 6 months and it’s getting really frustrating.