When multi-select and batch editing is enabled, it would be nice to have a built-in feature to edit those rows all at once. Something like a popup with an editor for each column selected.

The basic idea:

Requirements
- Selection mode has to be multiple. Both row and cell should be fine.
- Edit mode: Batch preferably for performance reason (but allow other?).

Features
- [Grid widget] New multiEdit() method. Accepts an optional rowIndexes[], rowGuids[] or cellGuids[] parameter. If parameter array > 1 or parameter is null and selection > 1, open edit popup for specified or selected cells accordingly.
- [Toolbar] Built-in Edit button. Disabled if selection <= 1.
- [Popup] A popup with an editor for each selected (or passed into argument) columns.

The popup could potentially be template based but I don't know how this would work out with the editors not always available. I leave that up to you :)

Instead of a popup, it could also be (or as an extra optional feature maybe?) a fixed row right under the header that appears when you try to edit multiple rows. Sorta like the filter row but for editing.

Perhaps you could even give this feature it's own edit mode. That mode would display the fixed row permanently and would disable individual editing. Upon selection, that fixed row would take up the value of the selected row (or display "Multiple" when the values differ) and changing that value would set all the selected cells of the column to that value. 

PS. I saw the other multi-row editing suggestion. It was mainly about having mutliple rows opened for edit at once. I understand the technicalities behind why it's a bit of a mess to do. This is not what I'm asking for here. My suggestion involves having only a single editor per column