(from bug 4677) Windows does not properly handle both shift keys. There are two main problems: a) Both keys send VK_SHIFT. This is similar to how both control keys send VK_CONTROL. The difference is that the right control (and alt, etc.) key has the extended bit set to tell it apart from the left. Both shift keys were available on the original PC keyboard, so there is no extended bit for the right one. The only way to tell them apart is to look at the scan code. b) Windows fails to keep track of state when both are pressed at the same time. This sequence doesn't work: 1. Press left shift 2. Press right shift 3. Release left shift 4. Release right shift Step 3 never generates an event in this scenario, leaving the key permanently pressed as far as VNC is concerned.
Browsers seem to detect the right shift and send the proper Javascript event for it. However they do indeed suffer from the mentioned bug that a release gets lost and the state gets screwed up.
Mostly fixed upstream: https://github.com/TigerVNC/tigervnc/commit/30b3f926cbafe58e699a1e8893d96817ded21f3d
> * Pressing right and left shift should send Shift_R and Shift_L respectively Yup. Works well. > * Pressing both shift keys and releasing one should send release events for both when on Windows (platform limitation) Almost. It's when the last one is released you get the events. This is in line with the initial description for this bug so the acceptance criteria needs to be adjusted here.
