Emulator

What's the problem? Describe what went wrong.

When 3D is set to SBS, both the SBS and TAB hotkeys turn 3D off.
When 3D is set to TAB, both the SBS and TAB hotkeys do nothing.
When 3D is off or in any other mode, both the SBS and TAB hotkeys enable TAB mode.
The other 3D Mode toggle hotkeys behave correctly, disabling 3D if it is using that mode and switching to that mode if 3D is off or in another mode.
This bug only occurs when using the Qt interface.

Is the issue present in the latest development version? For future reference, please also write down the version number of the latest development version.

Yes, it is present through 5.0-8108.

Which is the first broken version?

This has been an issue since hotkeys were first implemented in Qt (#5510).

What are your PC specifications? (CPU, GPU, Operating System, more)

CPU: i3-4170 @ 3.70 GHz
GPU: (integrated graphics)
Operating System: Windows 10 Home version 1803

What have you tried to resolve the issue?

I changed line 353 in Source/Core/DolphinQt2/HotkeyScheduler.cpp to

if (Config::Get(Config::GFX_STEREO_MODE) != (IsHotkey(HK_TOGGLE_STEREO_SBS) ? StereoMode::SBS : StereoMode::TAB))

and this partially fixed the issue, so both hotkeys act like properly-functioning TAB hotkeys.
When I then switched the second and third arguments of the ternary operator on line 360, it acted like it originally did, but both hotkeys only enabled SBS mode.
The last thing I did was switch the second and third arguments of the change I made to line 353, which gave me two properly-functioning SBS hotkeys.

Is there anything else that can help developers narrow down the issue? (e.g. logs, screenshots,
configuration files, savefiles, savestates)

It seems like the SBS hotkey is being detected as the TAB hotkey.
When it is properly detected, adding in the first modification I tried (or splitting to two separate functions like the 3DVision mode) should fix the issue completely.