Please provide basic information like operating system etc.

Every bug report needs basic info, but please. Maybe i can be a bit more specific in this way.
My computer is a Mac OsX 10.7, I'm using the last official public Gimp build, v. 2.8.10 from Lisanet.
My input devices are a Apple keyboard (large one) with a Microsoft intellipoint mouse and a wacom bamboo tablet MTE-450.

To paint i naturally use the wacom tablet, one of the buttons on my pen is configured to use the shortcut "space" to pan the image, the other button on the pen should scroll in/out (zoom), but does not. Scrolling works in tabs with long lists for brushes, textures, color palettes, ect. only. But that is another story (bug report 725885)

To reconstruct the bug in question, try to drag (pan) your zoomed image for a while and for some seconds, using your pen button. Already a single move creates some delay when you release the button.
Sometimes i get the sticky bug already after 2 moves.  I use panning a lot, when i paint on details, for example.

So this doesn't happen when you use the actual space bar on your keyboard?

The keyboard space bar works well. 

The pen buttons however, have problems with panning, and i assume to know whats
the cause too. Sometimes, and it happens relatively often, i hold my pen in
given angle (more acute than obtuse) over my tablet, and the input methods flip
from keyboard to mouse inputs-also back and forth, in the baddest case, and
then, for a second long. The clue that input methods change are that i get
selected other colors, brushes, ect. which i effectively used with the mouse
and not with the tablet. 

To be sincere, i wonder why input methods cannot share the same
configuration-i'd welcome a proper setting in preferences if you really want
this feature. For me, input methods should use -the same- configuration. (same
brushes, colors, ect.)

This conflict could be related on how gimp handles input methods when a tablet
is in use.

So this happens because your pen leaves the proximity of the tablet if you hold it like this? Or why is the angle of importance?

(In reply to comment #5)
> So this happens because your pen leaves the proximity of the tablet if you hold
> it like this? Or why is the angle of importance?

my pen IS in the proximity of the tablet, but i hold the pen above for some millimeters on the tablet surface. 
You can configure this feature in your wacom preferences, because you need not always to touch the tablet surface, when moving your mouse only, for example.

about the angle:
the bug happens more often when i hold the pen in a obtuse angle.

correction, i wrote:
>about the angle:
>the bug happens more often when i hold the pen in a obtuse angle.

should be acute angle, sorry

maybe this story with the pen angle sounds a bit silly, but it isnt.
Sometimes Gimp becomes confused and incessantly flips back and forth between mouse and tablet input, when i hold the pen in a given angle. The panning-sticky bug is related in some way with the input methods.

I'd welcome if you could create an option in Gimp's preferences, where the use could set which input method to prefer:
-mouse input
-tablet input

So it is actually the switching between the different input devices that causes the sticking button effect?

(In reply to Michael Schumacher from comment #9)
> So it is actually the switching between the different input devices that
> causes the sticking button effect?

in my eyes yes. As already said, Gimp becomes confused and incessantly flips back and forth between mouse and tablet input, when working with pen and tablet. Solving this dynamic input device bug could not hurt on the way.

Does this still happen with 2.8.14?

(In reply to Michael Schumacher from comment #11)
> Does this still happen with 2.8.14?

no more as i can think of, maybe we can close this bug report.

Thanks. Let's close it. Please reopen if it happens again.