Left clicking inside emulator window disables all inputs

[chuckythecat]

Game: Serious Sam: Next Encounter (US version, ID: G3BE9G) Issue: When I bind mouse left click ("Click 0") to R button on first gamecube controller, pressing left click disables all inputs (including the left click (R button) itself, so I can't, for example, hold left click to do a charged cannon shot). Binding gamecube R button to a keyboard key does not produce this issue. Observations:

1. This issue only occurs if I click inside the emulator window, if I left click on window title bar, it works just fine, all inputs go through.
2. If I click left mouse button once and then hold it inside the emulator window then inputs do actually go through for some reason.
3. Issue does not occur with right mouse button. With RMB bound to B button (reload) it works just fine.

Emulator version: Can reproduce on Preview 1, 2 and 3. On regular Dolphin 5.0-21460 issue does not occur.