First post, by emendelson
I've only seen this problem in my own project, which runs an application, not a game, so I don't expect any of the devs to respond unless the same problem occurs in games.
In both text and graphic modes, under every output= option that I've tried, the mouse cursor in my DOS program sometimes "stalls" near one of the edges of the window. In a VESA 1024X768 graphics screen, the mouse might stall two-thirds of the way down the window. I use a custom 43-line video mode (details in a moment), and sometimes the mouse stalls near the bottom, top, or right border. Sometimes, by moving the mouse in many directions, I can get it to move into the area where it wouldn't go before, but that doesn't always work.
The problem seems to vary slightly with different output= settings. I mostly use openglhq where the problem seems less bad than in other settings, but it occurs in all settings.
One of my users reports that he can fix the problem by clicking in the "DOSBox" string in the title bar of the DOSBox window. I can't reproduce that, but perhaps he is simply seeing the effect of moving the mouse around.
I see this problem in standard VESA modes and in my custom text mode. In int10_modes.cpp I've replaced mode 3 with this:
{ 0x003 ,M_TEXT ,720 ,688 ,80 ,43 ,9 ,16 ,8 ,0xB8000 ,0x4000 ,100 ,688 ,80 ,688 ,0 }, /* EM mod! */
I've experimented by increasing the plength setting from 0x1000 to 0x2000 and 0x4000 (as it is now), but that was just an incompetent guess on my part, and didn't do any good.
I would be very grateful for any help with this.