In MSVS this is a very useful feature.
It allows to pin a watch to the source editor.
See small description here (tip 3)
In general when you pin a watch to the source editor it stays there (pair name|value) and scrolls together with sources. It allows to quickly observe required variable values while debugging.
Unfortunately, it will not make it into 7.4.
this feature we would like to see implemented in the upcoming release. Be based on our experience and feedback from users, we think it will be useful and desired feature both from NetBeans and Studio prospective. Is there any chance that it can get into 8.1?