Boox Color Series User Manual page 37

Floating Toolbar
You can choose to activate the Floating Toolbar for the first time when
you open a file. Or you can go to Settings / Floating Toolbar Settings to
enable it and customize the function buttons in the Floating Toolbar.
The Floating Toolbar includes: Hide, Scribble, Enable Palm Rejection,
Menu, Prev Page, Next Page, Cancel (Progress)
Long press on the Floating Toolbar, you can drag it around on the screen.
You can expand or contract the Toolbar to the edge to avoid cover any
text on the screen. When you need it, just swipe from either side of edge
to the other side to expand it.