SendInput keys sometimes missing.

[Light]

I have been trying to use a combination of Dragon NaturallySpeaking 12.5, NatLink and a Python extension, DragonFly 0.6.5 to translate voice commands into keyboard events. When the target window is Notepad, it seems work flawlessly, but when the target is a VirtualBox guest, some keys may be missed. I have debugged the DragonFly code, which uses a Python wrapper around the WinAPI call SendInput to generate the key presses and releases. I verified that the input to the SendInput looked correct during an incidence of this behavior.

I guessed VirtualBox devs would have a rough time reproducing this software setup, and I wasn't confident I could make an easy test case of SendInput. So, I set out to make an AutoHotkey script to demonstrate the issue:

space::
SendInput if{space}(){enter}{{}{enter}
;SendPlay if{space}(){enter}{{}{enter}
;SendEvent if{space}(){enter}{{}{enter}
return

; is a comment character and interestingly, the 1st and 3rd commands did work with Notepad but none produce any input other than a space with the VirtualBox guest (does this mean VirtualBox uses some kind of key hook?). I can't confirm which of those commands might use SendInput internally, but I can tell you I've tried compiling and running the script in elevated mode with no improvements.

I have tried posting about this issue on the forums already.

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.