diff --git a/resources/celerity/map.php b/resources/celerity/map.php
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -354,7 +354,7 @@
     'rsrc/js/application/auth/behavior-persona-login.js' => '9414ff18',
     'rsrc/js/application/config/behavior-reorder-fields.js' => '14a827de',
     'rsrc/js/application/conpherence/ConpherenceThreadManager.js' => 'bb928342',
-    'rsrc/js/application/conpherence/behavior-durable-column.js' => 'c81c2bba',
+    'rsrc/js/application/conpherence/behavior-durable-column.js' => 'a0216452',
     'rsrc/js/application/conpherence/behavior-menu.js' => 'de5579b4',
     'rsrc/js/application/conpherence/behavior-pontificate.js' => '21ba5861',
     'rsrc/js/application/conpherence/behavior-quicksand-blacklist.js' => '7927a7d3',
@@ -584,7 +584,7 @@
     'javelin-behavior-diffusion-locate-file' => '6d3e1947',
     'javelin-behavior-diffusion-pull-lastmodified' => '2b228192',
     'javelin-behavior-doorkeeper-tag' => 'e5822781',
-    'javelin-behavior-durable-column' => 'c81c2bba',
+    'javelin-behavior-durable-column' => 'a0216452',
     'javelin-behavior-error-log' => '6882e80a',
     'javelin-behavior-fancy-datepicker' => 'c51ae228',
     'javelin-behavior-global-drag-and-drop' => 'bbdf75ca',
@@ -1569,6 +1569,16 @@
       'javelin-request',
       'phabricator-shaped-request',
     ),
+    'a0216452' => array(
+      'javelin-behavior',
+      'javelin-dom',
+      'javelin-stratcom',
+      'javelin-behavior-device',
+      'javelin-scrollbar',
+      'javelin-quicksand',
+      'phabricator-keyboard-shortcut',
+      'conpherence-thread-manager',
+    ),
     'a0b57eb8' => array(
       'javelin-behavior',
       'javelin-dom',
@@ -1731,16 +1741,6 @@
       'javelin-stratcom',
       'javelin-vector',
     ),
-    'c81c2bba' => array(
-      'javelin-behavior',
-      'javelin-dom',
-      'javelin-stratcom',
-      'javelin-behavior-device',
-      'javelin-scrollbar',
-      'javelin-quicksand',
-      'phabricator-keyboard-shortcut',
-      'conpherence-thread-manager',
-    ),
     'c90a04fc' => array(
       'javelin-dom',
       'javelin-dynval',
diff --git a/webroot/rsrc/js/application/conpherence/behavior-durable-column.js b/webroot/rsrc/js/application/conpherence/behavior-durable-column.js
--- a/webroot/rsrc/js/application/conpherence/behavior-durable-column.js
+++ b/webroot/rsrc/js/application/conpherence/behavior-durable-column.js
@@ -83,9 +83,13 @@
 
     // When we activate the column, adjust the tablet breakpoint so that we
     // convert the left side of the screen to tablet mode on narrow displays.
-    var breakpoint = JX.Device.getTabletBreakpoint();
-    JX.Device.setTabletBreakpoint(
-      visible ? (breakpoint + columnWidth) : (breakpoint - columnWidth));
+    var breakpoint;
+    if (visible) {
+      breakpoint = minimumViewportWidth + columnWidth;
+    } else {
+      breakpoint = minimumViewportWidth;
+    }
+    JX.Device.setTabletBreakpoint(breakpoint);
 
     JX.Stratcom.invoke('resize');
   }