When using OverTheSpot XIM style with rxvt-2.7.10, rxvt does not properly update the spot location after text was received from the IM.
My assumption: In command.c:684, any X11 event is saved in the rxvt_t struct, even those that were previously filtered out by XFilterEvent. This makes rxvt_IMSendSpot check the wrong event afterwards and believe it does not need to update the spot location.
I included a small patch that seems to fix the issue for me.
Note, for XIM to work on Solaris 10/iiimx I also needed to include Kazutoshi Kubota's suggestion http://email@example.com/msg00237.html.