diff --git a/hmml_to_html/mock_filter.html b/hmml_to_html/mock_filter.html
index 7c4e1d3..c5c2a73 100644
--- a/hmml_to_html/mock_filter.html
+++ b/hmml_to_html/mock_filter.html
@@ -103,13 +103,22 @@
         <div class="player_container">
             <div class="video_container" data-videoId="ug5WkCROkOk"></div>
             <div class="markers_container riscy">
-                <div data-timestamp="60" class="marker authored cat_hardware research" data-ref="https://en.wikipedia.org/wiki/Logic_gate,0-7356-0505-X">
-                    <div class="content"><span class="timecode">1:00</span><span class="author" style="color: hsl(257, 87%, 26%);">insofaras</span> Some text referring to <a href="https://handmade.network/m/zilarrezko" target="blank" style="color: hsl(83, 75%, 26%); text-decoration: none">Zilarrezko</a> about this thing<sup>1</sup> regarding circuit design he saw in Code<sup>2</sup><span class="categories"><div class="category hardware"></div></span></div>
+                <div data-timestamp="12" class="marker cat_rendering cat_hardware">
+                    <div class="content"><span class="timecode">0:12</span>Basic test with a little longer text<span class="categories"><div class="category rendering"></div><div class="category hardware"></div></span></div>
                     <div class="progress faded">
-                        <div class="content"><span class="timecode">1:00</span><span class="author" style="color: hsl(257, 87%, 26%);">insofaras</span> Some text referring to <a href="https://handmade.network/m/zilarrezko" target="blank" style="color: hsl(83, 75%, 26%); text-decoration: none">Zilarrezko</a> about this thing<sup>1</sup> regarding circuit design he saw in Code<sup>2</sup><span class="categories"><div class="category hardware"></div></span></div>
+                        <div class="content"><span class="timecode">0:12</span>Basic test with a little longer text<span class="categories"><div class="category rendering"></div><div class="category hardware"></div></span></div>
                     </div>
                     <div class="progress main">
-                        <div class="content"><span class="timecode">1:00</span><span class="author" style="color: hsl(257, 87%, 26%);">insofaras</span> Some text referring to <a href="https://handmade.network/m/zilarrezko" target="blank" style="color: hsl(83, 75%, 26%); text-decoration: none">Zilarrezko</a> about this thing<sup>1</sup> regarding circuit design he saw in Code<sup>2</sup><span class="categories"><div class="category hardware"></div></span></div>
+                        <div class="content"><span class="timecode">0:12</span>Basic test with a little longer text<span class="categories"><div class="category rendering"></div><div class="category hardware"></div></span></div>
+                    </div>
+                </div>
+                <div data-timestamp="60" class="marker authored cat_rendering cat_hardware research" data-ref="https://en.wikipedia.org/wiki/Logic_gate,0-7356-0505-X">
+                    <div class="content"><span class="timecode">1:00</span><span class="author" style="color: hsl(257, 87%, 26%);">insofaras</span> Some text referring to <a href="https://handmade.network/m/zilarrezko" target="blank" style="color: hsl(83, 75%, 26%); text-decoration: none">Zilarrezko</a> about this thing<sup>1</sup> regarding circuit design he saw in Code<sup>2</sup><span class="categories"><div class="category rendering"></div><div class="category hardware"></div></span></div>
+                    <div class="progress faded">
+                        <div class="content"><span class="timecode">1:00</span><span class="author" style="color: hsl(257, 87%, 26%);">insofaras</span> Some text referring to <a href="https://handmade.network/m/zilarrezko" target="blank" style="color: hsl(83, 75%, 26%); text-decoration: none">Zilarrezko</a> about this thing<sup>1</sup> regarding circuit design he saw in Code<sup>2</sup><span class="categories"><div class="category rendering"></div><div class="category hardware"></div></span></div>
+                    </div>
+                    <div class="progress main">
+                        <div class="content"><span class="timecode">1:00</span><span class="author" style="color: hsl(257, 87%, 26%);">insofaras</span> Some text referring to <a href="https://handmade.network/m/zilarrezko" target="blank" style="color: hsl(83, 75%, 26%); text-decoration: none">Zilarrezko</a> about this thing<sup>1</sup> regarding circuit design he saw in Code<sup>2</sup><span class="categories"><div class="category rendering"></div><div class="category hardware"></div></span></div>
                     </div>
                 </div>
                 <div data-timestamp="176" class="marker" data-ref="&#945;">
@@ -222,34 +231,59 @@ filterModeElement.addEventListener("click", function(ev) {
     }
 });
 
-var filterTopics = document.querySelectorAll(".filter_topics > .filter_content");
+var filterTopics = document.querySelectorAll(".filter_content");
 for (var i = 0; i < filterTopics.length; ++i)
 {
     filterTopics[i].addEventListener("click", function(ev) {
+        // NOTE(matt): Useful test
+        // if(this.parentNode.className == "filter_topics")
 
+        var selectedCategory = this.childNodes[1].classList[2];
+
+        var categorisedMarkers = document.querySelectorAll("." + selectedCategory);
         if(!(this.classList.contains("off")))
         {
+            //console.log(this);
             this.classList.add("off");
+            for (var j = 0; j < categorisedMarkers.length; ++j)
+            {
+                //console.log(categorisedMarkers[j]);
+                {
+                    //console.log("Disabling %s", selectedCategory);
+                    categorisedMarkers[j].classList.add("off");
+                }
+            }
         }
         else
         {
             this.classList.remove("off");
+            for (var j = 0; j < categorisedMarkers.length; ++j)
+            {
+                //console.log("Enabling %s", selectedCategory);
+                categorisedMarkers[j].classList.remove("off");
+            }
         }
-    });
-}
 
-var filterMedia = document.querySelectorAll(".filter_media > .filter_content");
-for (var i = 0; i < filterMedia.length; ++i)
-{
-    filterMedia[i].addEventListener("click", function(ev) {
-
-        if(!(this.classList.contains("off")))
+        var testMarkers = document.querySelectorAll(".cat_" + selectedCategory);
+        for(var k = 0; k < testMarkers.length; ++k)
         {
-            this.classList.add("off");
-        }
-        else
-        {
-            this.classList.remove("off");
+            var Skipping = 1;
+            var testCategories = testMarkers[k].querySelectorAll(".category");
+            for(var l = 0; l < testCategories.length; ++l)
+            {
+                if(!(testCategories[l].classList.contains("off")))
+                {
+                    var Skipping = 0;
+                }
+            }
+            if(Skipping)
+            {
+                testMarkers[k].classList.add("skip");
+            }
+            else
+            {
+                testMarkers[k].classList.remove("skip");
+            }
         }
     });
 }