The Find feature in Adobe Acrobat Pro X has bothered me for some time now:
The click-targets to find the previous or next occurrence of your search term are tiny. Minuscule. Verging on microscopic. Let’s say I’m searching a 600 page PDF on SharePoint and I’m looking for occurrences of the term workflow. As I click next repeatedly, trying to find the relevant section, I find that it’s very easy for my cursor to edge over just a little bit and close the Find dialog.
(Yes, I know: I can just keep pressing Enter and avoid this issue.)