Bug 580412 - Add a couple-pixel threshold before tabs start dragging [r=dietrich, a=beltzner]

browser/base/content/tabview/drag.js

@@ -118,8 +118,8 @@ Drag.prototype = {
 
     // OH SNAP!
 
-    // if we aren't holding down the meta key...
-    if (!Keys.meta) {
+    // if we aren't holding down the meta key or have trenches disabled...
+    if (!Keys.meta && !Trenches.disabled) {
       // snappable = true if we aren't a tab on top of something else, and
       // there's no active drop site...
       let snappable = !(this.item.isATabItem &&

browser/base/content/tabview/items.js

@@ -187,7 +187,10 @@ Item.prototype = {
       stop: function() {
         drag.info.stop();
         drag.info = null;
-      }
+      },
+      // The minimum the mouse must move after mouseDown in order to move an 
+      // item
+      minDragDistance: 3
     };
 
     // ___ drop
@@ -592,64 +595,67 @@ Item.prototype = {
       // ___ mousemove
       var handleMouseMove = function(e) {
         // positioning
-        var mouse = new Point(e.pageX, e.pageY);
-        var box = self.getBounds();
-        box.left = startPos.x + (mouse.x - startMouse.x);
-        box.top = startPos.y + (mouse.y - startMouse.y);
-
-        self.setBounds(box, true);
-
-        // drag events
+        var mouse = new Point(e.pageX, e.pageY);		
         if (!startSent) {
-          if (typeof self.dragOptions.start == "function")
-            self.dragOptions.start.apply(self,
-                [startEvent, {position: {left: startPos.x, top: startPos.y}}]);
-
-          startSent = true;
+          if(Math.abs(mouse.x - startMouse.x) > self.dragOptions.minDragDistance ||
+             Math.abs(mouse.y - startMouse.y) > self.dragOptions.minDragDistance) {
+            if (typeof self.dragOptions.start == "function")
+              self.dragOptions.start.apply(self,
+                  [startEvent, {position: {left: startPos.x, top: startPos.y}}]);
+            startSent = true;
+          }
         }
+        if (startSent) {
+          // drag events
+          var box = self.getBounds();
+          box.left = startPos.x + (mouse.x - startMouse.x);
+          box.top = startPos.y + (mouse.y - startMouse.y);
 
-        if (typeof self.dragOptions.drag == "function")
-          self.dragOptions.drag.apply(self, [e]);
+          self.setBounds(box, true);
 
-        // drop events
-        var best = {
-          dropTarget: null,
-          score: 0
-        };
+          if (typeof self.dragOptions.drag == "function")
+            self.dragOptions.drag.apply(self, [e]);
 
-        droppables.forEach(function(droppable) {
-          var intersection = box.intersection(droppable.bounds);
-          if (intersection && intersection.area() > best.score) {
-            var possibleDropTarget = droppable.item;
-            var accept = true;
-            if (possibleDropTarget != dropTarget) {
-              var dropOptions = possibleDropTarget.dropOptions;
-              if (dropOptions && typeof dropOptions.accept == "function")
-                accept = dropOptions.accept.apply(possibleDropTarget, [self]);
+          // drop events
+          var best = {
+            dropTarget: null,
+            score: 0
+          };
+
+          droppables.forEach(function(droppable) {
+            var intersection = box.intersection(droppable.bounds);
+            if (intersection && intersection.area() > best.score) {
+              var possibleDropTarget = droppable.item;
+              var accept = true;
+              if (possibleDropTarget != dropTarget) {
+                var dropOptions = possibleDropTarget.dropOptions;
+                if (dropOptions && typeof dropOptions.accept == "function")
+                  accept = dropOptions.accept.apply(possibleDropTarget, [self]);
+              }
+
+              if (accept) {
+                best.dropTarget = possibleDropTarget;
+                best.score = intersection.area();
+              }
+            }
+          });
+
+          if (best.dropTarget != dropTarget) {
+            var dropOptions;
+            if (dropTarget) {
+              dropOptions = dropTarget.dropOptions;
+              if (dropOptions && typeof dropOptions.out == "function")
+                dropOptions.out.apply(dropTarget, [e]);
             }
 
-            if (accept) {
-              best.dropTarget = possibleDropTarget;
-              best.score = intersection.area();
+            dropTarget = best.dropTarget;
+
+            if (dropTarget) {
+              dropOptions = dropTarget.dropOptions;
+              if (dropOptions && typeof dropOptions.over == "function")
+                dropOptions.over.apply(dropTarget, [e]);
             }
           }
-        });
-
-        if (best.dropTarget != dropTarget) {
-          var dropOptions;
-          if (dropTarget) {
-            dropOptions = dropTarget.dropOptions;
-            if (dropOptions && typeof dropOptions.out == "function")
-              dropOptions.out.apply(dropTarget, [e]);
-          }
-
-          dropTarget = best.dropTarget;
-
-          if (dropTarget) {
-            dropOptions = dropTarget.dropOptions;
-            if (dropOptions && typeof dropOptions.over == "function")
-              dropOptions.over.apply(dropTarget, [e]);
-          }
         }
 
         e.preventDefault();

browser/base/content/tabview/trench.js

@@ -466,9 +466,11 @@ var Trenches = {
   //   nextId - (integer) a counter for the next <Trench>'s <Trench.id> value.
   //   showDebug - (boolean) whether to draw the <Trench>es or not.
   //   defaultRadius - (integer) the default radius for new <Trench>es.
+  //   disabled - (boolean) whether trench-snapping is disabled or not.
   nextId: 0,
   showDebug: false,
   defaultRadius: 10,
+  disabled: false,
 
   // ---------
   // Variables: snapping preferences; used to break ties in snapping.

browser/base/content/test/tabview/Makefile.in

@@ -45,6 +45,7 @@ include $(topsrcdir)/config/rules.mk
 
 _BROWSER_FILES = \
                  browser_tabview_apptabs.js \
+                 browser_tabview_bug580412.js \
                  browser_tabview_bug587040.js \
                  browser_tabview_bug587990.js \
                  browser_tabview_bug591706.js \