As a science major, I greatly appreciate Sumatra for accessing my text books. Often I’ll find myself flipping between the front and the back of the textbook to move between problems and solutions, or taking a windows ‘snip’ of the solutions section. Alternatively, I sometimes make two copies of a text book in order to view the solutions and problems simultaneously.
To the request: allow multiple instances of a single PDF to be opened in separate tabs, ideally by selecting the current tab and clicking a “clone tab” option.