Bug introduced in 10.2 and fixed in 10.3
Consider this simple code:
Manipulate[n, {n, 1, 5}]
When we evaluate it, we'll get
Now try to click on the little plus sign to expand the controls. Suddenly the slider will jump forward, in this case to value 4.
I'm almost certain that this is bug. Is there something we can do to mitigate this unexpected this behavior? I'm using Mathematica 10.2 64bit on Windows 10.



Appearance -> "Open"to the definition of yourManipulatevariable (i.e.{n, 1, 5, Appearance -> "Open"}), so that the control will start out in the open state. – MarcoB Sep 03 '15 at 03:05Manipulators, they (I) probably don't care about details :) – Kuba Sep 03 '15 at 06:28{n, 1, 5, Appearance -> "Open"}as well as{{n, 1}, 1, 5, Appearance -> "Open"}doesn't work as a workaround for my Mathematica 10.2 on Win10. Did you try it? – Karsten7 Oct 05 '15 at 16:30