Index: src/window.cpp
===================================================================
--- src/window.cpp	(revision 24916)
+++ src/window.cpp	(working copy)
@@ -1898,10 +1898,13 @@ static EventState HandleWindowDragging()
 
 			if (_settings_client.gui.window_snap_radius != 0) {
 				const Window *v;
+				const Window *wt;
 
 				int hsnap = _settings_client.gui.window_snap_radius;
 				int vsnap = _settings_client.gui.window_snap_radius;
 				int delta;
+				int a; // Top border of gap
+				int b; // Bottom border of gap
 
 				FOR_ALL_WINDOWS_FROM_BACK(v) {
 					if (v == w) continue; // Don't snap at yourself
@@ -1910,31 +1913,144 @@ static EventState HandleWindowDragging()
 						/* Your left border <-> other right border */
 						delta = abs(v->left + v->width - x);
 						if (delta <= hsnap) {
-							nx = v->left + v->width;
-							hsnap = delta;
+							a = w->top;
+							b = w->top + w->height;
+							if (v->top > a) a = v->top;
+							if (v->top + v->height < b) b = v->top + v->height;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->left < v->left + v->width) && (wt->left + wt->width > v->left + v->width)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}	
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->left < v->left + v->width) && (wt->left + wt->width > v->left + v->width)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}										
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}
+								}
+							}
+							if (a >= b) {
+								nx = x;
+							} else {
+								nx = v->left + v->width;
+								hsnap = delta;
+							}
 						}
-
 						/* Your right border <-> other left border */
 						delta = abs(v->left - x - w->width);
 						if (delta <= hsnap) {
-							nx = v->left - w->width;
-							hsnap = delta;
+							a = w->top;
+							b = w->top + w->height;
+							if (v->top > a) a = v->top;
+							if (v->top + v->height < b) b = v->top + v->height;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->left < v->left) && (wt->left + wt->width > v->left)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}	
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->left < v->left + v->width) && (wt->left + wt->width > v->left + v->width)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}										
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}
+								}
+							}
+							if (a >= b) {
+								nx = x;
+							} else {
+								nx = v->left - w->width;
+								hsnap = delta;
+							}
 						}
 					}
-
 					if (w->top + w->height >= v->top && w->top <= v->top + v->height) {
-						/* Your left border <-> other left border */
+					/* Your left border <-> other left border */
 						delta = abs(v->left - x);
 						if (delta <= hsnap) {
-							nx = v->left;
-							hsnap = delta;
+							a = w->top;
+							b = w->top + w->height;
+							if (v->top > a) a = v->top;
+							if (v->top + v->height < b) b = v->top + v->height;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->left < v->left) && (wt->left + wt->width > v->left)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}	
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->left < v->left + v->width) && (wt->left + wt->width > v->left + v->width)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}										
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}
+								}
+							}
+							if (a >= b) {
+								nx = x;
+							} else {
+								nx = v->left;
+								hsnap = delta;
+							}
 						}
-
 						/* Your right border <-> other right border */
 						delta = abs(v->left + v->width - x - w->width);
 						if (delta <= hsnap) {
-							nx = v->left + v->width - w->width;
-							hsnap = delta;
+							a = w->top;
+							b = w->top + w->height;
+							if (v->top > a) a = v->top;
+							if (v->top + v->height < b) b = v->top + v->height;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->left < v->left + v->width) && (wt->left + wt->width > v->left + v->width)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}	
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->left < v->left + v->width) && (wt->left + wt->width > v->left + v->width)){
+										if (wt->top > b){continue;}
+										if (wt->top > a && wt->top + wt->height < b){continue;}
+										if (wt->top < a && wt->top + wt->height > b){a = 0; b = 0; break;}										
+										if (wt->top > a && wt->top + wt->height >= b){b = wt->top; continue;}
+										if (wt->top <= a && wt->top + wt->height > a){a = wt->top + wt->height; continue;}
+								}
+							}
+							if (a >= b) {
+								nx = x;
+							} else {
+								nx = v->left + v->width - w->width;
+								hsnap = delta;
+							}
 						}
 					}
 
@@ -1942,15 +2058,72 @@ static EventState HandleWindowDragging()
 						/* Your top border <-> other bottom border */
 						delta = abs(v->top + v->height - y);
 						if (delta <= vsnap) {
-							ny = v->top + v->height;
-							vsnap = delta;
+							a = w->left;
+							b = w->left + w->width;
+							if (v->left > a) a = v->left;
+							if (v->left + v->width < b) b = v->left + v->width;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->top < v->top + v->height) && (wt->top + wt->height > v->top + v->height)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}	
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->top < v->top + v->height) && (wt->top + wt->height > v->top + v->height)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}										
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}
+								}
+							}
+							if (a >= b) {
+								ny = y;
+							} else {
+								ny = v->top + v->height;
+								vsnap = delta;
+							}
 						}
-
 						/* Your bottom border <-> other top border */
 						delta = abs(v->top - y - w->height);
 						if (delta <= vsnap) {
-							ny = v->top - w->height;
-							vsnap = delta;
+							a = w->left;
+							b = w->left + w->width;
+							if (v->left > a) a = v->left;
+							if (v->left + v->width < b) b = v->left + v->width;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->top < v->top) && (wt->top + wt->height > v->top)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}	
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->top < v->top + v->height) && (wt->top + wt->height > v->top + v->height)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}										
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}
+								}
+							}
+							if (a >= b) {
+								ny = y;
+							} else {
+								ny = v->top - w->height;
+								vsnap = delta;
+							}
 						}
 					}
 
@@ -1958,15 +2131,73 @@ static EventState HandleWindowDragging()
 						/* Your top border <-> other top border */
 						delta = abs(v->top - y);
 						if (delta <= vsnap) {
-							ny = v->top;
-							vsnap = delta;
+							a = w->left;
+							b = w->left + w->width;
+							if (v->left > a) a = v->left;
+							if (v->left + v->width < b) b = v->left + v->width;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->top < v->top) && (wt->top + wt->height > v->top)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}	
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->top < v->top + v->height) && (wt->top + wt->height > v->top + v->height)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}										
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}
+								}
+							}
+							if (a >= b) {
+								ny = y;
+							} else {
+								ny = v->top;
+								vsnap = delta;
+							}
 						}
 
 						/* Your bottom border <-> other bottom border */
 						delta = abs(v->top + v->height - y - w->height);
 						if (delta <= vsnap) {
-							ny = v->top + v->height - w->height;
-							vsnap = delta;
+							a = w->left;
+							b = w->left + w->width;
+							if (v->left > a) a = v->left;
+							if (v->left + v->width < b) b = v->left + v->width;
+							FOR_ALL_WINDOWS_FROM_BACK_FROM(wt, v->z_front){
+								if (wt == w) break;
+								if ((wt->top < v->top + v->height) && (wt->top + wt->height > v->top + v->height)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}	
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}	
+								}
+							}
+							wt = NULL;
+							FOR_ALL_WINDOWS_FROM_FRONT_FROM(wt, w->z_front){
+								if (wt == v) break;
+								if ((wt->top < v->top + v->height) && (wt->top + wt->height > v->top + v->height)){
+										if (wt->left > b){continue;}
+										if (wt->left > a && wt->left + wt->width < b){continue;}
+										if (wt->left < a && wt->left + wt->width > b){a = 0; b = 0; break;}										
+										if (wt->left > a && wt->left + wt->width >= b){b = wt->left; continue;}
+										if (wt->left <= a && wt->left + wt->width > a){a = wt->left + wt->width; continue;}
+								}
+							}
+							if (a >= b) {
+								ny = y;
+							} else {
+								ny = v->top + v->height - w->height;
+								vsnap = delta;
+							}
 						}
 					}
 				}