Index: src/window.cpp
===================================================================
--- src/window.cpp	(revision 24919)
+++ src/window.cpp	(working copy)

@@ -1868,6 +1870,70 @@ int GetMainViewBottom()
 static bool _dragging_window; ///< A window is being dragged or resized.
 
 /**
+ * Checks border visibility between edges of dragging window.
+ * @param v Window to which snap.
+ * @param w Dragging window.
+ * @param is_horisontal True if snap to left or to right border.
+ * @param snap_to_left_or_top_border True if snap to left or to top border.
+ * @return Bool variable. True if window can snap and false if can't.
+ */
+bool SnapChecking(const Window *v, const Window *w,  bool is_horisontal, bool snap_to_left_or_top_border)
+{														
+	int a;					// upper border of gap
+	int b;					// lower border of gap
+	int v_edge;				
+	int wt_edge_first;
+	int wt_edge_second;
+	int wt_first_border;
+	int wt_second_border;
+	int windows_sort_direction = 1;
+	const Window *wt;
+		
+	if (is_horisontal){
+		a = (v->top > w->top) ? v->top : w->top;
+		b = (v->top + v->height < w->top + w->height) ? v->top + v->height : w->top + w->height;
+	} else {
+		a = (v->left > w->left) ? v->left : w->left;
+		b = (v->left + v->width < w->left + w->width) ? v->left + v->width : w->left + w->width;
+	}
+
+	wt = v;
+	while (true){
+		if (wt->z_front == NULL) windows_sort_direction = -1;
+		if (windows_sort_direction == 1){
+			wt = wt->z_front;
+		} else {
+			wt = wt->z_back;
+		}
+		if (wt == w) continue;
+		if (wt == v || wt == v->z_back) break; // Second condition need if snap to window which over dragging window
+
+		if (is_horisontal){
+			wt_first_border = wt->top;
+			wt_second_border = wt->top + wt->height;
+			v_edge = (snap_to_left_or_top_border) ? v->left : v->left + v->width;
+			wt_edge_first = wt->left;
+			wt_edge_second = wt->left + wt->width;
+		} else {
+			wt_first_border = wt->left;
+			wt_second_border = wt->left + wt->width;
+			v_edge = (snap_to_left_or_top_border) ? v->top : v->top + v->height;
+			wt_edge_first = wt->top;
+			wt_edge_second = wt->top + wt->height;			
+		}	
+
+		if (IsInsideMM(v_edge, wt_edge_first, wt_edge_second)){
+			if (wt_first_border > b || wt_second_border < a) continue;
+			if (wt_first_border > a && wt_second_border < b) continue; 
+			if (wt_first_border < a && wt_second_border > b) {a = 0; b = 0; break;}
+			if (wt_first_border <= a && wt_second_border > a) {a = wt_second_border; continue;}
+			if (wt_first_border > a && wt_second_border >= b) {b = wt_first_border; continue;}	
+		}		
+	}
+	return (a >= b) ? false : true;
+}
+
+/**
  * Handle dragging/resizing of a window.
  * @return State of handling the event.
  */
@@ -1910,31 +1976,36 @@ 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;
+							if (SnapChecking(v, w,  true, false)){
+								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;
+							if (SnapChecking(v, w,  true, true)){
+								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;
+							if (SnapChecking(v, w,  true, true)){
+								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;
+							if (SnapChecking(v, w,  true, false)){
+								nx = v->left + v->width - w->width;
+								hsnap = delta;
+							}
 						}
 					}
 
@@ -1942,15 +2013,18 @@ 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;
+							if (SnapChecking(v, w,  false, false)){
+								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;
+							if (SnapChecking(v, w,  false, true)){
+								ny = v->top - w->height;
+								vsnap = delta;
+							}
 						}
 					}
 
@@ -1958,15 +2032,19 @@ static EventState HandleWindowDragging()
 						/* Your top border <-> other top border */
 						delta = abs(v->top - y);
 						if (delta <= vsnap) {
-							ny = v->top;
-							vsnap = delta;
+							if (SnapChecking(v, w,  false, true)){
+								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;
+							if (SnapChecking(v, w,  false, false)){
+								ny = v->top + v->height - w->height;
+								vsnap = delta;
+							}
 						}
 					}
 				}