No way of controlling gateTime at present in nightlies
As it says on the tin.
Select any note from any score.
Open the Inspector (F8)
Expected result: There should be a section to control the gateTime of a note as in 1.3 Note Properties
Actual result: gateTime control is missing from the Inspector
This means the only way of controlling the gateTime of a note is to hack the mscx file - not a very friendly option :)
Windows 8 Pro
MuseScore 2 commit 3e51505913a5aadabc23c643a93e56497efca2c5