Have a convenient way to display horizontally reduced index
Submitted by Mathieu Dupuy
Link to original bug (#645010)
Description
Sometime the index is very large, and the beginning is often uninteresting since it is just chapter numbers and whitespace padding. When horizontally reducing the index, the useful side of the index get trimmed, and only whitespace and number remain. A solution like a scrollbar (as present in Foxit Reader), allowing to keep displayed only the useful part of the index, keeping its position through vertical scrolling of the index, would be welcome.