Index: unix/tkUnixSelect.c
==================================================================
--- unix/tkUnixSelect.c
+++ unix/tkUnixSelect.c
@@ -163,10 +163,17 @@
     retr.encFlags = TCL_ENCODING_START;
     retr.nextPtr = pendingRetrievals;
     Tcl_DStringInit(&retr.buf);
     pendingRetrievals = &retr;
 
+    /*
+     * Delete the property to indicate that no parameters are supplied for
+     * the conversion request.
+     */
+
+    XDeleteProperty(winPtr->display, retr.winPtr->window, retr.property);
+
     /*
      * Initiate the request for the selection. Note: can't use TkCurrentTime
      * for the time. If we do, and this application hasn't received any X
      * events in a long time, the current time will be way in the past and
      * could even predate the time when the selection was made; if this

