I discovered a problem in InDesign with the DPI scaling set bigger than 100% in the display settings. One major reason for me, why I upgraded from CS5 to CC is the possibilty to rescale UIs in Photoshop and InDesign. Sadly it seems to be impossible to use the guideline grid, when the scaling is turned on, or in other words it is invisble.
I already tried to change respective settings in the preference menue in ID or to send the grid to the background or front, but no luck there. Only thing worked for me is to turn off scaling in the system settings, which makes it nearly impossible to work in full resolution 2560 x 1440 px.
Probably interesting: there seems to be a familiar problem with Flash CC and the fontsize, aka drawing with the artpen and the DPI scaling.
It would be great if someone could help with that, or has a workaround/hints.