Find out what process registered a global hotkey? (Windows API)

Run the tool (for me, it’s at C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\Tools\spyxx_amd64.exe)
In the menu bar, select Spy -> Log messages… (or hit Ctrl + M)
Check All Windows in System in the Additional Windows frame
Switch to the Messages tab
Click the Clear All button
Select WM_HOTKEY in the listbox, or check Keyboard in Message Groups (if you’re OK with more potential noise)
Click the OK button
Press the hotkey in question (Win + R, for example)
Select the WM_HOTKEY line in the Messages (All Windows) window, right click, and select Properties… in the context menu
In the Message Properties dialog, click the Window Handle link (this will be the handle for the window that received the message)
Click the Synchronize button on the Window Properties dialog. This will show the window in the main Spy++ window treeview.
On the Window Properties dialog, select the Process tab
Click the Process ID link. This will show you the process (In my Win + R case: EXPLORER)