diff --git a/core/modules/filters.js b/core/modules/filters.js
index 0de78b685..a5fbef221 100644
--- a/core/modules/filters.js
+++ b/core/modules/filters.js
@@ -107,6 +107,18 @@ exports.operators = {
 					break;
 				case "system":
 					return "for(title in source) {if(" + op + "this.getTiddler(title).isSystem()) {$tw.utils.pushTop(subResults,title);}}";
+				case "missing":
+					if(operator.prefix === "!") {
+						return "for(title in source) {$tw.utils.pushTop(subResults,title);}";
+					} else {
+						return "var m = this.getMissingTitles(); for(t=0; t<m.length; t++) {$tw.utils.pushTop(subResults,m[t]);}";
+					}
+				case "orphan":
+					if(operator.prefix === "!") {
+						return "var m = this.getOrphanTitles(); for(title in source) {if(m.indexOf(title) === -1) {$tw.utils.pushTop(subResults,title);}}";
+					} else {
+						return "var m = this.getOrphanTitles(); for(t=0; t<m.length; t++) {$tw.utils.pushTop(subResults,m[t]);}";
+					}
 				default:
 					throw "Unknown operand for 'is' filter operator";
 			}
@@ -123,6 +135,14 @@ exports.operators = {
 					break;
 				case "system":
 					return "for(r=subResults.length-1; r>=0; r--) {if(" + op + "this.getTiddler(subResults[r]).isSystem()) {subResults.splice(r,1);}}";
+				case "missing":
+					return "t = this.getMissingTitles(); for(r=subResults.length-1; r>=0; r--) {if(" + op + "!$tw.utils.hop(t,subResults[r])) {subResults.splice(r,1);}}";
+				case "orphan":
+					if(operator.prefix === "!") {
+						return "t = this.getOrphanTitles(); for(r=subResults.length-1; r>=0; r--) {if(t.indexOf(subResults[r]) === -1) {subResults.splice(r,1);}}";
+					} else {
+						return "t = this.getOrphanTitles(); for(r=subResults.length-1; r>=0; r--) {if(t.indexOf(subResults[r]) !== -1) {subResults.splice(r,1);}}";
+					}
 				default:
 					throw "Unknown operand for 'is' filter operator";
 			}
diff --git a/core/modules/wiki.js b/core/modules/wiki.js
index 71e29b2f7..cf7d1aa56 100644
--- a/core/modules/wiki.js
+++ b/core/modules/wiki.js
@@ -256,12 +256,69 @@ exports.forEachTiddler = function(/* [sortField,[excludeTag,]]callback */) {
 	}
 };
 
+/*
+Return an array of tiddler titles that are directly linked from the specified tiddler
+*/
+exports.getTiddlerLinks = function(title) {
+	var self = this;
+	// We'll cache the links so they only get computed if the tiddler changes
+	return this.getCacheForTiddler(title,"links",function() {
+		// Parse the tiddler
+		var parser = self.parseTiddler(title);
+		// Count up the links
+		var links = [],
+			checkParseTree = function(parseTree) {
+				for(var t=0; t<parseTree.length; t++) {
+					var parseTreeNode = parseTree[t];
+					if(parseTreeNode.type === "element" && parseTreeNode.tag === "$link" && parseTreeNode.attributes.to.type === "string") {
+						var value = parseTreeNode.attributes.to.value;
+						if(links.indexOf(value) === -1) {
+							links.push(value);
+						}
+					}
+					if(parseTreeNode.children) {
+						checkParseTree(parseTreeNode.children);
+					}
+				}
+			};
+		if(parser) {
+			checkParseTree(parser.tree)
+		}
+		return links;
+	});
+};
+
+/*
+Return a hashmap of tiddler titles that are referenced but not defined. Each value is the number of times the missing tiddler is referenced
+*/
 exports.getMissingTitles = function() {
-	return []; // Todo
+	var self = this,
+		missing = [];
+// We should cache the missing tiddler list, even if we recreate it every time any tiddler is modified
+	this.forEachTiddler(function(title,tiddler) {
+		var links = self.getTiddlerLinks(title);
+		$tw.utils.each(links,function(link) {
+			if(!self.tiddlerExists(link) && missing.indexOf(link) === -1) {
+				missing.push(link);
+			}
+		});
+	});
+	return missing;
 };
 
 exports.getOrphanTitles = function() {
-	return []; // Todo
+	var self = this,
+		orphans = this.getTiddlers();
+	this.forEachTiddler(function(title,tiddler) {
+		var links = self.getTiddlerLinks(title);
+		$tw.utils.each(links,function(link) {
+			var p = orphans.indexOf(link);
+			if(p !== -1) {
+				orphans.splice(p,1);
+			}
+		});
+	});
+	return orphans; // Todo
 };
 
 exports.getSystemTitles = function() {
diff --git a/core/templates/MoreSideBar.tid b/core/templates/MoreSideBar.tid
new file mode 100644
index 000000000..b27a80d88
--- /dev/null
+++ b/core/templates/MoreSideBar.tid
@@ -0,0 +1,16 @@
+title: $:/templates/MoreSideBar
+
+<div class="tw-tab-set">
+<div class="tw-tab-buttons"><$button type="set" set="$:/state/moreSideBarTabSet" setTo="missingTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">Missing</$button><$button type="set" set="$:/state/moreSideBarTabSet" setTo="orphanTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">Orphans</$button><$button type="set" set="$:/state/moreSideBarTabSet" setTo="systemTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">System</$button></div>
+<div class="tw-tab-contents">
+<$reveal type="match" state="$:/state/moreSideBarTabSet" text="missingTab" qualifyTiddlerTitles="yes">
+<$list filter="[is[missing]sort[title]]" itemClass="tw-menu-list-item"/>
+</$reveal>
+<$reveal type="match" state="$:/state/moreSideBarTabSet" text="orphanTab" qualifyTiddlerTitles="yes">
+<$list filter="[is[orphan]sort[title]]" itemClass="tw-menu-list-item"/>
+</$reveal>
+<$reveal type="match" state="$:/state/moreSideBarTabSet" text="systemTab" qualifyTiddlerTitles="yes">
+<$list filter="[is[system]sort[title]]" itemClass="tw-menu-list-item"/>
+</$reveal>
+</div>
+</div>
diff --git a/core/templates/SideBar.tid b/core/templates/SideBar.tid
index 1ad5091ac..0b196c633 100644
--- a/core/templates/SideBar.tid
+++ b/core/templates/SideBar.tid
@@ -2,19 +2,20 @@ title: $:/templates/SideBar
 
 <!-- The implementation of tabs here is currently a bit unreadable -->
 <div class="tw-tab-set">
-<div class="tw-tab-buttons"><$button type="set" set="myTabset" setTo="openTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">Open</$button><$button type="set" set="myTabset" setTo="allTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">All</$button><$button type="set" set="myTabset" setTo="systemTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">System</$button><$button type="set" set="myTabset" setTo="toolsTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">Tools</$button></div>
+<div class="tw-tab-buttons"><$button type="set" set="$:/state/sideBarTabSet" setTo="openTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">Open</$button><$button type="set" set="$:/state/sideBarTabSet" setTo="allTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">All</$button><$button type="set" set="$:/state/sideBarTabSet" setTo="toolsTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">Tools</$button><$button type="set" set="$:/state/sideBarTabSet" setTo="moreTab" qualifyTiddlerTitles="yes" selectedClass="tw-tab-selected">More</$button></div>
 <div class="tw-tab-contents">
-<$reveal type="match" state="myTabset" text="openTab" qualifyTiddlerTitles="yes">
+<$reveal type="match" state="$:/state/sideBarTabSet" text="openTab" qualifyTiddlerTitles="yes">
 <$list filter="[list[$:/StoryList]]" history="$:/HistoryList" itemClass="tw-menu-list-item"/>
 </$reveal>
-<$reveal type="match" state="myTabset" text="allTab" qualifyTiddlerTitles="yes">
+<$reveal type="match" state="$:/state/sideBarTabSet" text="allTab" qualifyTiddlerTitles="yes">
 <$list filter="[!is[system]sort[title]]" itemClass="tw-menu-list-item"/>
 </$reveal>
-<$reveal type="match" state="myTabset" text="systemTab" qualifyTiddlerTitles="yes">
-<$list filter="[is[system]sort[title]]" itemClass="tw-menu-list-item"/>
-</$reveal>
-<$reveal type="match" state="myTabset" text="toolsTab" qualifyTiddlerTitles="yes">
+<$reveal type="match" state="$:/state/sideBarTabSet" text="toolsTab" qualifyTiddlerTitles="yes">
 {{$:/templates/ControlPanel}}
 </$reveal>
 </div>
+<$reveal type="match" state="$:/state/sideBarTabSet" text="moreTab" qualifyTiddlerTitles="yes">
+{{$:/templates/MoreSideBar}}
+</$reveal>
+</div>
 
diff --git a/core/wiki/moreSideBarTabSet.tid b/core/wiki/moreSideBarTabSet.tid
new file mode 100644
index 000000000..9e19a5931
--- /dev/null
+++ b/core/wiki/moreSideBarTabSet.tid
@@ -0,0 +1,3 @@
+title: $:/state/moreSideBarTabSet-tiddlerTitle:$:/templates/MoreSideBar;templateTitle:$:/templates/MoreSideBar;-tiddlerTitle:$:/templates/SideBar;templateTitle:$:/templates/SideBar;-tiddlerTitle:$:/templates/PageTemplate;-
+
+missingTab
\ No newline at end of file
diff --git a/core/wiki/myTabset.tid b/core/wiki/myTabset.tid
deleted file mode 100644
index ebe1c1b00..000000000
--- a/core/wiki/myTabset.tid
+++ /dev/null
@@ -1,3 +0,0 @@
-title: myTabset-tiddlerTitle:$:/templates/SideBar;templateTitle:$:/templates/SideBar;-tiddlerTitle:$:/templates/PageTemplate;-
-
-openTab
\ No newline at end of file
diff --git a/core/wiki/sideBarTabSet.tid b/core/wiki/sideBarTabSet.tid
new file mode 100644
index 000000000..ca6fe1dc9
--- /dev/null
+++ b/core/wiki/sideBarTabSet.tid
@@ -0,0 +1,3 @@
+title: $:/state/sideBarTabSet-tiddlerTitle:$:/templates/SideBar;templateTitle:$:/templates/SideBar;-tiddlerTitle:$:/templates/PageTemplate;-
+
+openTab
\ No newline at end of file