Plugging out Microsoft Nano Tranceiver (USB mouse) causes PS2 keyboard to cease functioning

[Yuri]

I have Microsoft USB Explorer Touch mouse. It works fine, but when I 
plug out its (wireless) USB dongle, keyboard also stops working.
Plugging the dongle back in enables the keyboard again. Plugging in some 
other USB mouse instead doesn't make keyboard work again.

There were two keyboard devices defined before this mouse was first 
plugged in: kbd0 at atkbd0 and kbd1 at kbdmux0, see messages below.
This mouse defines the new keyboard device kbd2 at ukbd0.
When the dongle is plugged out, these two items (kbd2 at ukbd0) 
disappear from /dev, leaving all the same devices that existed before. 
Except keyboard becomes disfunctional.

What could be a problem with this USB mouse? Looks like it interacts 
with the previous setup and leaves something modified when plugged out.

Yuri

PS: This of course isn't the major usability issue since, when plugged 
in, everything works. Nevertheless, I can't plug it out without losing 
the keyboard.


---messages (kbd related during boot)--
kbd1 at kbdmux0
<...skipped...>
atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
atkbd0: [GIANT-LOCKED]

---messages (plug out)---
Jan 14 14:30:59 eagle kernel: ugen1.2: <Microsoft> at usbus1 (disconnected)
Jan 14 14:30:59 eagle kernel: ukbd0: at uhub1, port 1, addr 2 (disconnected)
Jan 14 14:30:59 eagle kernel: ums0: at uhub1, port 1, addr 2 (disconnected)
Jan 14 14:30:59 eagle kernel: uhid0: at uhub1, port 1, addr 2 (disconnected)

---messages (plug in)---
Jan 14 14:31:09 eagle kernel: ugen1.2: <Microsoft> at usbus1
Jan 14 14:31:09 eagle kernel: ukbd0: <Microsoft Microsoft Nano 
Transceiver v1.0, class 0/0, rev 2.00/6.74, addr 2> on usbus1
Jan 14 14:31:09 eagle kernel: kbd2 at ukbd0
Jan 14 14:31:09 eagle kernel: ums0: <Microsoft Microsoft Nano 
Transceiver v1.0, class 0/0, rev 2.00/6.74, addr 2> on usbus1
Jan 14 14:31:09 eagle kernel: ums0: 5 buttons and [XYZT] coordinates ID=26
Jan 14 14:31:09 eagle kernel: ums0: 0 buttons and [T] coordinates ID=0
Jan 14 14:31:09 eagle kernel: uhid0: <Microsoft Microsoft Nano 
Transceiver v1.0, class 0/0, rev 2.00/6.74, addr 2> on usbus1

$ ls -l /dev/*kbd*
crw-------  1 root  wheel    0,  57 Jan  4 11:50 /dev/atkbd0
lrwxr-xr-x  1 root  wheel         6 Jan  4 11:50 /dev/kbd0 -> atkbd0
lrwxr-xr-x  1 root  wheel         7 Jan  4 11:50 /dev/kbd1 -> kbdmux0
lrwxr-xr-x  1 root  wheel         5 Jan 14 14:38 /dev/kbd2 -> ukbd0
crw-------  1 root  wheel    0,  13 Jan  4 11:50 /dev/kbdmux0
crw-------  1 root  wheel    0, 182 Jan 14 14:38 /dev/ukbd0