Made hotzones for empty columns fill right down to the footer to improve drop...

Made hotzones for empty columns fill right down to the footer to improve drop success chances. Fixed a bug where in empty columns blocks couldn't be dropped right at the top of the column

htdocs/js/views.js

@@ -674,8 +674,6 @@ function ViewManager() {
                 var columnContainerPosition   = elementPosition(self.columnContainer);
                 var columnContainerDimensions = elementDimensions(self.columnContainer);
 
-                var viewportDimensions = getViewportDimensions();
-
                 var footerDimensions = getElementDimensions('footer', self.bottomPane);
                 var footerPosition   = getElementPosition('footer', self.bottomPane);
 
@@ -694,12 +692,22 @@ function ViewManager() {
                 // Column with no blockinstances
                 var columnContent = getFirstElementByTagAndClassName('div', 'column-content', i);
                 var hotzone = self.createHotzone(columnContent, appendChildNodes, true);
-                setElementPosition(hotzone, getElementPosition(columnContent, self.columnContainer));
+
+                var footerDimensions = getElementDimensions('footer', self.bottomPane);
+                var footerPosition   = getElementPosition('footer', self.bottomPane);
+
+                setElementPosition(hotzone, {x: getElementPosition(columnContent, self.columnContainer).x, y: 0});
                 setElementDimensions(hotzone, {
                     w: getElementDimensions(columnContent).w,
-                    h: getViewportDimensions().h - getElementPosition(i).y - 60 // FIXME: math here is dodgy, unproven
+                    h: footerPosition.y + footerDimensions.h
                 });
 
+                // The column content may have whitespace in it. This
+                // whitespace causes the box to respect line-height, which
+                // pushes down where the blocks appear when dragged into the
+                // column. Removing all the children nodes fixes this
+                replaceChildNodes(columnContent);
+
                 previousHotzone = hotzone;
             }
         });