Merge pull request #871 from simonwelsh/3.1-scroll

Calculate where to scroll to based off the position in the div

javascript/CMSMain.Tree.js

@@ -142,17 +142,27 @@
 			}
 		});
 
-		// Scroll tree down to context of the current page
+		// Scroll tree down to context of the current page, if it isn't
+		// already visible
 		$('.cms-tree a.jstree-clicked').entwine({
-            onmatch: function(){
+			onmatch: function(){
-                var self = this,
+				var self = this,
-                	panel = self.parents('.cms-panel-content');
+					panel = self.parents('.cms-panel-content'),
+					scrollTo;
 
-                panel.animate({
+				if(self.offset().top < 0 ||
-                    scrollTop: self.offset().top - (panel.height() / 2)
+					self.offset().top > panel.height() - self.height()) {
-                }, 'slow'); 
+					// Current scroll top + our current offset top is our
-            }
+					// position in the panel
-        });
+					scrollTo = panel.scrollTop() + self.offset().top
+								+ (panel.height() / 2);
+
+					panel.animate({
+						scrollTop: scrollTo
+					}, 'slow');
+				}
+			}
+		});
 	});
 
 }(jQuery));