What version are you running?
2.5.11. This was not an issue in the previous version of Review Board we were using (2.4?).
What's the URL of the page containing the problem?
happens when viewing any diff
What steps will reproduce the problem?

view the diff
double-click on a word in the code (eg. a function name) with the intention of copying and searching for it
unwanted comment box shows up and the word gets unselected


What is the expected output? What do you see instead?
This happens when in the flow of understanding a piece of code, when you double-click on a function name to copy it and search for it. When the comment box shows up it interrupts that flow by un-selecting the word so you can't copy it, plus now there's a comment box in the way.
What operating system are you using? What browser?
Chromium 45.0/Ubuntu 14.04
Please provide any additional information below.
I can see why you may have implemented the feature on purpose, but IMO it is an extremely frustrating bug because of the way it interrupts the flow of understanding the code.
This one misfeature has singlehandedly caused me to curse at my computer about 10x more than I used to. Please fix it or find another way to allow easy code navigation.