simultaneous keys

Borland Sidekick is started by pressing LeftShift and RightShift simultaneously. This worked well in 1.1.4.0, but somewhere between 1.1.4.0 and 1.1.4.8 (can't narrow it down further at the moment) dosemu has developed problems with detecting the simultaneous key presses.

In 1.1.4.8 and later it is very difficult to get Sidekick to pop up (and then to stay put). Sidekick pops up briefly, then apparently thinks that both keys are not depressed after all, and disappears again. Has something involving timing and the keyboard changed recently?

Regards, Jan