Find Next and Find Previous arrow icons get dim

The Find command (ctrl-f) produces a window with two arrows for Find Next and Find Previous. What causes those arrows to dim? This seems to presage a crash of LO or, if I catch the problem soon enough, precedes the Writer document auto-scrolling to the bottom and then if I try to find something further up it may find it but it immediately takes me back to the bottom, so I can’t use the found match and I have to close and reopen the file or else tolerate a crash of all of LibreOffice. This is in Writer, in LO versions 4.x and for openSuse 13.2 Linux. I started a bug thread at but need to identify steps leading to the problem and lately noticed the dimming before the autoscrolling. The dimming is intermittent. Any idea about what I might have done to cause the dimming?