Input Device settings are lost when opening a canvas

Reproduces consistently on Windows 8 with Wacom Intous tablet -
Every time when I open a document, my stylus ‘forgets’ its ‘pressure’ function (i.e. the cursor follows the tip, but drawing/moving stuff doesn’t work.
The only workaround I’ve found so far is to open the “Input Devices” dialog, reselect my tablet (which causes the “Pressure” and X/Y tilt to be magically filled), switch to “window” tracking mode, save, switch to “screen” tracking mode, save and close the dialog.

I also have sometime the same trouble with an external usb lost pointer click (the displacement is not lost , “just” the click)

In my case, i did’t find a way to reproduce it …but i have found the same workaround (“Input Devices” dialog) to retreive it.