I've got a bunch of cursor control remaps that I've used for a long time in apps like Chrome and Slack, most of which include alt in the shortcut. In the Win7 version of Slack, they work fine, but in Windows 10, pressing alt opens the app's menu as a popup. This seems to be a change in the Electron platform that Slack uses to wrap their web app as a desktop app.
The problem is, if I use a remap like this to remap ctrl-alt-J to ctrl-left arrow:
The cursor moves, but then the Slack menu pops up,
even without releasing the physical alt key. So somehow, Slack heard an alt up event, which triggers the menu, even though I haven't released the alt key.
Is there any way to suppress the alt up event from being triggered after I press the shortcut keys, so that the app doesn't see it?