This includes an optimization to zero the height and width of existing thumbnail canvases, when they are removed and recreated during rotation of the document. (Credit goes to nnethercote, who initially found this in PR 4920.)
In old versions of the viewer, anchor links were used to be able to scroll a page into view. Since we for quite some time have had a `scrollIntoView` function which handles this, the anchor links are no longer necessary and I believe that they can be removed. Doing so will reduce the total number of DOM elements in the viewer.
For most documents this patch will probably not make much of a difference performance wise, but for very long (1000+ pages) documents this could help performance especially on lower powered hardware.
Now that [bug 649849](https://bugzilla.mozilla.org/show_bug.cgi?id=649849) has been fixed, adding support for `-moz-appearance: none`, the arrow is now too close to the text in the zoom box. This is currently only an issue in Nightly, but assuming the patch doesn't get backed out, this will soon affect all versions of Firefox.
The only simple solution I could find seems to be removing `*-appearance: none` rules from the CSS. I haven't been able to find any easier solutions that still looks the same with/without bug 649849.
Currently if you manage to e.g. open the console (with <kbd>Ctrl</kbd>+<kbd>Shift</kbd>+<kbd>K</kbd>) before the viewer is initialized, the following will be printed in the console: `TypeError: pdfViewer is null`.
This doesn't cause any actual errors, but nevertheless it seems like something we should avoid.
Followup to PR 5413.
When a search term isn't found, the background color of the findInput is supposed to change (to red). This is currently not working as intended, because the CSS rule is not being applied correctly. (It seems that this broke in PR 2208.)
This patch also changes the background color to match the one used in the native Firefox findbar, since the old color seemed a bit too pink.