With a list "select" widget with multiple selection allowed, how to enable the selection of multiple items with a touchscreen device?
Drag/drop or swipe cannot be used for selection, it is already used to scroll the scrollbar of the list
Click / tap cannot be used because this is used to select a new single item (see the UX in Windows File Explorer or Mac Finder)
Double-click / double-tap is already used to open the selected element (e.g. like in a file explorer)
Important: my real use case is something close to a File Explorer list of files:
Note: This is linked to Select multiple items with HTML <select> with a touchscreen but here it is about the general UX design rather than the code implementation.
Not a duplicate of What is the best UI for multi-selecting from a list? because the file-explorer-like UX is very different.

