I seem to have exactly the same problem as this person: http://forums.adobe.com/thread/618752 He also has example code that purports to demonstrate the problem.
Basically, I have a webpage consisting of 2 frames: in the right hand frame, a PDF, which my users all view in Adobe Reader (generally 9.3), and a left hand frame which contains a form. The form contains a couple of inputs which use the excellent TextBoxList JQuery tool for auto-completion.
Since we upgraded people to Firefox 3.6, certain keystrokes no longer get to the input elements on the left hand frame — notably, cursor keys and enter. Arrow keys are ignored, and enter submits the form, which is highly undesirable. Everything worked fine on Firefox 3.5, and works great on platforms where we don’t use Adobe Reader.
Anyone had any experience of similar issues with plugins intercepting keystrokes intended for adjacent frames, or got any tips on how best to work around this? Unfortunately the workflow is such that having the document displayed in one frame and the form with autocompletes in the frame adjacent is highly desirable.
Updated to add: this appears to be an open bug in Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=550709
It seems there is no real answer to this — it’s a bug in Firefox and/or Adobe Reader and all we can do is work around it. The good news is that I have failed to recreate the bug in either Firefox 3.5 or 4.0beta, so my advice to anyone encountering the same issue would be to stick with 3.5 until 4 appears.