The Data list that shows all of the segments that you have defined in the system has a standard behavior to show options in a pull-down when you select any given row. For some rows in the segment grid the options do not appear.
Download and install the latest patch which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.
Steps to Duplicate
1. Go to Marketing and Communication 2. Choose Segments 3. In this list Search on text contained in a segment 4. Notice that you can select any row and the pull-down options are available on the row 5. Now search for different text 6. At this point some rows do not present the pull-down options although the "chevron" points up. 7. You may have to repeat this process a few times, but once it starts to happen, it persists.