Add next / prev to Data Window for seqable

[zikajk]

Problem description: When checking multiple values in :seqable (or :indexed), you have to select one value, open it, and then go back to select another one.

• It is not ideal as you need to remember which values you have visited.

Proposed solution: Add next/prev arrows to Data Window to switch to another value in seq, smth like

(It is a very minor issue, more a suggestion)