This behavior is highly disturbing a normal workflow.
Before restarting I had reproducibly the following effect:
I copy the settings of one picture pressing ctrl alt shift + c, I accept the dialog by pressing enter. then the focus changed into the keyword field. (the same happened when I pressed the button using the mouse!)
Normally the focus soesn't go anywhere.
Lightroom version: 3.5 RC 
Operating system: Windows 7 Ultimate Edition
Version: 6.1 
Application architecture: x64
System architecture: x64
Physical processor count: 4
Processor speed: 3.4 GHz
Built-in memory: 7934.1 MB
Real memory available to Lightroom: 7934.1 MB
Real memory used by Lightroom: 629.2 MB (7.9%)
Virtual memory used by Lightroom: 743.7 MB
Memory cache size: 277.9 MB
System DPI setting: 96 DPI
Desktop composition enabled: Yes
Displays: 1) 1920x1200, 2) 1920x1200
This is indeed a problem.
I had previously been editing the filename field, but had closed it out.
I invoked a plugin, and after dismissing the first dialog box, filename field is open for edit again - this is NOT proper behavior.
This is a problem!
The ONLY thing I did between these two screenshots, is click the 'Cancel' button:
This problem is not fixed and I'm using Lightroom CC 2015.4.
I have a long list of Keywords in "Keyword List". Whenever I click a keyword that is further down the list to, one forbid, select it, the focus jump to the filter box. I need to scroll back down again to finally selecting by, wait for it... clicking.
being in the development module and pressing Ctrl Shift C and quitting the dialog via Enter you cannot move to the next image with the arrow keys any more!
As this situation often happens in my workflow this really drives me crazy!