No descriptive texts in the Help bar for the first 4 icons
First 6 icons are fore segment panes, two last ones for the tabbed pane, this isn't clear. place a tab around the blue arrows?
Second row: the concept of a page, how clear is that for the grid? Isn't there a better name? If not, place a page symbol around the blue arrows?
Both commands don't work with Windows 10.
I think the concept of a "page" is quite irritating here (especially for any newbie), as it is not a physical page nor any other page. IMHO the best tool tip would be "Previous 50 segments"/"Next 50 segments" respectively "Previous x segments"/"Next x segments" (as x can be set in the options).
Same for "First page"/"Last page".