Well, this is called the "dimension palette" (see this 2015 SOLIDWORKS Help - Dimension Palette and this: http://www.javelin-tech.com/blog/2011/07/drawing-dimension-palette/ and this: SOLIDWORKS 2015 Dimension Palette - YouTube )
It should be showing up always to the upper right of the dimension that you have selected, but I agree....based on the size of the dimension and the how far out you are zoomed and how many dimensions you have selected, it does always seem to be in a different place.
Personally, I never use it. Probably because I did not know it was there until after I had gotten used to using the dimension properties screen on the left. That is always in the same place.
But in the end....as far as a hotkey is concerned, you might be able to modify the macro in this post to use on yours: Hotkey for dimension decimal places