WEB UI > display Selection Toolbar on top of header toolbar

When items are selected in a data table / grid listing, an actions toolbar is currently displayed below the app header.

The app header contains actions related to the view, the actions toolbar contains actions related to the selection. Having 2 rows of actions is really disturbing: some of them are the same, you just perform it on different items.
For example:

• header 'Add to collection' add the current doc to a collection,
• toolbar 'Add to collection' action add the selected items to a collection.