--- mgdiff.c.orig	Thu Apr 19 15:10:41 2001
+++ mgdiff.c	Sat Apr 21 00:18:05 2001
@@ -137,6 +137,7 @@
 
 static struct screenstate {
     Block *b;
+    Block *lastSelected;
     int topline;
     int leftcol;
     int sindex, findex[2];
@@ -724,7 +725,6 @@
 	dagcb = XtGetGC (children[1], GCForeground|GCBackground, &gc_values);
 	been_here = 1;
     }
-
     for (i = 0; i < 3; i++) {
 	XtVaGetValues (children[i],
 		       XmNwidth, &width[i],
@@ -1079,7 +1079,6 @@
 	};
 	werror_long (toplevel, "Wrong Application Defaults", array, sizeof (array) / sizeof (array[0]));
     }
-
     if (debug_flag) {
 	XSetErrorHandler (x_error_handler);
 	XtAppSetErrorHandler (app, xt_error_handler);
@@ -1174,6 +1173,7 @@
     }
 
     newss.b = di->first;
+    newss.lastSelected= NULL;
     newss.topline = newss.sindex = newss.findex[LEFT] = newss.findex[RIGHT] = 0;
 
     mainw = XtVaCreateManagedWidget ("mainw", xmMainWindowWidgetClass,
@@ -2133,6 +2133,7 @@
     handle_diff_errors (di);
 }
 
+
 static void refresh (void)
 {
     newss.b = di->first;
@@ -2196,6 +2197,115 @@
     exit ((di != NULL) ? di->status : 2);
 }
 
+void lost_selection ( Widget  widget, Atom* selection) { 
+	
+	if (debug_flag) {
+		fprintf(stderr,"selection lost on widget %p\n",widget);
+	}
+//	newss.lastSelected=NULL;
+}
+
+static Boolean do_selection(Widget widget, Atom*  selection, Atom*  target ,
+                            Atom*  type, XtPointer*  value, 
+			    unsigned long* length,int* format) {
+
+    Atom targets = XInternAtom(XtDisplay(widget), "TARGETS", False);
+    Atom *array;
+    char* result;
+    char* line;
+    int i,j;
+    Block *b= newss.lastSelected;
+    Chunk *chunk =NULL;
+    
+    if (debug_flag) {
+		fprintf(stderr,"selection request on widget %p\n",widget);
+    }
+
+   if (!b) return False;
+   
+   chunk = &(b->arr[b->selected]);
+   
+    if (*target == targets)
+    {
+	if (debug_flag) {
+		fprintf(stderr,"clipboards targets requested on widget %p\n",widget);
+        }	
+	/*
+	 * Handle request for data types
+	 */
+
+	if ((array = (Atom *)XtMalloc((unsigned)(sizeof(Atom) * 1))) == NULL)
+	    return False;
+	*value = (XtPointer)array;
+	array[0] = XA_STRING;
+	*type = XA_ATOM;
+	*format = sizeof(Atom) * 8;
+	*length = 5;
+	return True;
+    }
+    
+    if (*target == XA_STRING) {
+    	/*
+	 * request for string data !.
+	 */
+	if (debug_flag) {
+		fprintf(stderr,"string target requested on widget %p\n",widget);
+	}
+    	
+	/*
+	 * Iterate through the lines in the text block
+	 * summing the lengths
+	 */
+	*length=0;
+	for (i = 0; i < chunk->fsize; i++) {
+	   if ((chunk->wtext != NULL) && (chunk->wtext[i] != NULL)) {
+	       *length += (strlen(chunk->wtext[i])+1);
+	   } else {
+	       *length += (strlen(chunk->text[i])+1);
+	   }
+         }
+        *format = 8;	    /* 8 bits per char */
+	*type  = XA_STRING;
+	if (debug_flag) {
+		fprintf(stderr,"string length= %li\n",*length);
+	}
+
+    	*value = XtMalloc(*length);
+        result = (char*)(*value);
+ 	/*
+	 * Iterate through the lines in the text block
+	 * moving the data into the clipboard memblock
+	 */
+	for (i = 0; i < chunk->fsize; i++) {
+	   if ((chunk->wtext != NULL) && (chunk->wtext[i] != NULL)) {
+	      line = chunk->wtext[i] ;
+	   } else {
+	       line = chunk->text[i];
+	   }
+	   j =strlen(line);
+	   memcpy(result,line,j);
+	   result+=j;
+	   *(result++)= '\n';
+         }
+ 	
+	
+	if (debug_flag) {
+		fprintf(stderr,"all done string at= %p\n",*value);
+	}
+	if (!(*value)) {
+		return False;
+    	}
+	return True;
+    }
+    /* 
+     * Haven't found data type we know about!
+     */
+    return False;	
+}
+
+
+
+
 /* ARGSUSED2 */
 static void Select (Widget widget, XEvent *event, String *params, Cardinal *num_params)
 {
@@ -2203,11 +2313,19 @@
 	Block *b;
 	Dimension ypos, height;
 	int itemp, rect_height;
-
+	
+	Side x_selection = NEITHER;
+        Block *curr_x_block = newss.lastSelected;
+	
+	if (curr_x_block) {
+		x_selection = curr_x_block->selected;
+	}
+	
 	XtVaGetValues (widget, XmNheight, &height, NULL);
 
 	itemp = newss.sindex;
 	ypos = 0;
+	//Find selected chunk!.
 	for (b = newss.b; b != NULL; b = b->next) {
 	    if ((rect_height = font_height * (b->ssize - itemp)) > (int) height)
 		rect_height = height;
@@ -2222,12 +2340,15 @@
 			redraw_partial (textl, ypos, rect_height);
 			redraw_partial (textr, ypos, rect_height);
 			update_pixmaps ();
+			if (b == newss.lastSelected)
+				newss.lastSelected=NULL;
 		    }
 		    else if (widget == textr) {
 			b->selected = RIGHT;
 			redraw_partial (textl, ypos, rect_height);
 			redraw_partial (textr, ypos, rect_height);
 			update_pixmaps ();
+			newss.lastSelected=b;
 		    }
 		    else
 			assert (False);
@@ -2238,12 +2359,15 @@
 			redraw_partial (textl, ypos, rect_height);
 			redraw_partial (textr, ypos, rect_height);
 			update_pixmaps ();
+			newss.lastSelected=b;
 		    }
 		    else if (widget == textr) {
 			b->selected = NEITHER;
 			redraw_partial (textl, ypos, rect_height);
 			redraw_partial (textr, ypos, rect_height);
 			update_pixmaps ();
+			if (b == newss.lastSelected)
+				newss.lastSelected=NULL;
 		    }
 		    else
 			assert (False);
@@ -2253,10 +2377,24 @@
 		    redraw_partial (textl, ypos, rect_height);
 		    redraw_partial (textr, ypos, rect_height);
 		    update_pixmaps ();
+         	    newss.lastSelected=b;
 		    break;
 		default:
 		    assert (False);
 		    break;
+		}
+		if ( 
+				
+		       !newss.lastSelected 
+		     || (x_selection != newss.lastSelected->selected)
+	//	     || (newss.lastSelected != curr_x_block ) 
+		     
+		     ) {
+			XtDisownSelection(widget,XA_PRIMARY, CurrentTime);
+		}
+		if (newss.lastSelected) {
+			XtOwnSelection(widget,XA_PRIMARY, CurrentTime,
+					&do_selection,&lost_selection,NULL);
 		}
 		return;
 	    }