I've found that the middle and right buttons are swapped in Windows 98 when using a USB tablet in both Bochs 2.7 and Qemu 6.1.0.

Things I tested which aren't related:

• This doesn't affect Windows 98 SE or Me (or 95 where USB tablets don't seem to be supported).
• This doesn't affect regular USB mice, or (at least in Bochs - I didn't check in Qemu) PS/2 mice.
• This is unrelated to which GUI I use: I tried both Gtk and SDL for Qemu, and all of SDL, SDL 2, X and wx for Bochs.

None of the Windows versions I tested had updates installed (except 95 where I installed the USB supplement to no avail).

I tried in (an old version of) VirtualBox with a USB tablet but simply moving the cursor into the guest area of the window causes a blue screen with Windows 98 (no such problem with 98 SE).

Relatedly it seems that in Bochs with the SDL and SDL2 GUIs, the host's middle button isn't detected until you move the mouse, so it's harder to send a right click.

Before I file Bochs bugs (and one for Qemu if I remember), is anyone aware of swapped buttons with USB tablets or other absolute pointing devices being an issue in Windows 98? I don't know what real USB HID absolute pointing devices existed in 1998. I suspect that Windows might just have a bug and the solution is probably to have a configurable flag to swap the buttons in the emulated hardware, or maybe just limit it to an emulated two button device.

I checked and Qemu's changelog doesn't mention anything about this being fixed since 6.1.0 although I'd obviously try the latest version before filing a bug.