diff --git a/TODO.md b/TODO.md
index 59ec7784..7461a543 100644
--- a/TODO.md
+++ b/TODO.md
@@ -17,6 +17,8 @@
     - Special treatment for matrix.to URLs?
   - EventFile & Downloading (right click on media > save as...)
 
+  - Create room tabs brutal size transition
+
 - Refactoring
   - Room header elide detection
   - Use HBox for Profile
diff --git a/src/qml/Base/HButtonBackground.qml b/src/qml/Base/HButtonBackground.qml
index 52efb65b..b82902f7 100644
--- a/src/qml/Base/HButtonBackground.qml
+++ b/src/qml/Base/HButtonBackground.qml
@@ -11,7 +11,7 @@ Rectangle {
     property QtObject buttonTheme
 
 
-    Behavior on opacity { HNumberAnimation {} }
+    Behavior on opacity { HOpacityAnimator {} }
 
 
     Rectangle {
diff --git a/src/qml/Base/HButtonContent.qml b/src/qml/Base/HButtonContent.qml
index be91a266..eedbc1ea 100644
--- a/src/qml/Base/HButtonContent.qml
+++ b/src/qml/Base/HButtonContent.qml
@@ -16,7 +16,7 @@ HRowLayout {
     readonly property alias label: label
 
 
-    Behavior on opacity { HNumberAnimation {} }
+    Behavior on opacity { HOpacityAnimator {} }
 
 
     HIcon {
@@ -35,7 +35,7 @@ HRowLayout {
 
         ParallelAnimation {
             id: resetAnimations
-            HNumberAnimation { target: icon; property: "opacity"; to: 1 }
+            HOpacityAnimator { target: icon; to: 1 }
             HNumberAnimation { target: icon; property: "rotation"; to: 0 }
         }
 
diff --git a/src/qml/Base/HCheckBox.qml b/src/qml/Base/HCheckBox.qml
index c8ba8f2e..e6fb3855 100644
--- a/src/qml/Base/HCheckBox.qml
+++ b/src/qml/Base/HCheckBox.qml
@@ -17,7 +17,7 @@ CheckBox {
     property alias subtitle: subtitleText
 
 
-    Behavior on opacity { HNumberAnimation { factor: 2 } }
+    Behavior on opacity { HOpacityAnimator { factor: 2 } }
 
 
     indicator: Rectangle {
diff --git a/src/qml/Base/HListView.qml b/src/qml/Base/HListView.qml
index 2c485438..610370cf 100644
--- a/src/qml/Base/HListView.qml
+++ b/src/qml/Base/HListView.qml
@@ -31,7 +31,7 @@ ListView {
 
     add: Transition {
         ParallelAnimation {
-            HNumberAnimation { property: "opacity"; from: 0; to: 1 }
+            HOpacityAnimator { from: 0; to: 1 }
             HNumberAnimation { properties: "x,y"; from: 100 }
         }
     }
@@ -39,14 +39,14 @@ ListView {
     move: Transition {
         ParallelAnimation {
             // Ensure opacity goes to 1 if add/remove transition is interrupted
-            HNumberAnimation { property: "opacity"; to: 1 }
+            HOpacityAnimator { to: 1 }
             HNumberAnimation { properties: "x,y" }
         }
     }
 
     remove: Transition {
         ParallelAnimation {
-            HNumberAnimation { property: "opacity"; to: 0 }
+            HOpacityAnimator { to: 0 }
             HNumberAnimation { properties: "x,y"; to: 100 }
         }
     }
diff --git a/src/qml/Base/HOpacityAnimator.qml b/src/qml/Base/HOpacityAnimator.qml
new file mode 100644
index 00000000..7fab7366
--- /dev/null
+++ b/src/qml/Base/HOpacityAnimator.qml
@@ -0,0 +1,7 @@
+import QtQuick 2.12
+
+OpacityAnimator {
+    duration: theme.animationDuration * factor
+
+    property real factor: 1.0
+}
diff --git a/src/qml/Chat/RoomHeader.qml b/src/qml/Chat/RoomHeader.qml
index eb5818ab..5a662acd 100644
--- a/src/qml/Chat/RoomHeader.qml
+++ b/src/qml/Chat/RoomHeader.qml
@@ -132,7 +132,7 @@ Rectangle {
         icon.name: "reduced-room-buttons"
 
         Behavior on opacity {
-            HNumberAnimation { duration: buttonsAnimation.duration * 2 }
+            HOpacityAnimator { duration: buttonsAnimation.duration * 2 }
         }
     }
 }
diff --git a/src/qml/Chat/Timeline/EventImage.qml b/src/qml/Chat/Timeline/EventImage.qml
index 34d17498..632340df 100644
--- a/src/qml/Chat/Timeline/EventImage.qml
+++ b/src/qml/Chat/Timeline/EventImage.qml
@@ -88,7 +88,7 @@ HMxcImage {
         opacity: hover.hovered ? 0 : 1
         visible: opacity > 0
 
-        Behavior on opacity { HNumberAnimation {} }
+        Behavior on opacity { HOpacityAnimator {} }
     }
 
     EventImageTextBubble {
@@ -99,6 +99,6 @@ HMxcImage {
         opacity: hover.hovered ? 0 : 1
         visible: opacity > 0
 
-        Behavior on opacity { HNumberAnimation {} }
+        Behavior on opacity { HOpacityAnimator {} }
     }
 }
diff --git a/src/qml/Pages/AccountSettings/Profile.qml b/src/qml/Pages/AccountSettings/Profile.qml
index 46335339..62c9556d 100644
--- a/src/qml/Pages/AccountSettings/Profile.qml
+++ b/src/qml/Pages/AccountSettings/Profile.qml
@@ -81,7 +81,7 @@ HGridLayout {
                 (! avatar.mxc && overlayHover.hovered) ? 0.8 : 0.7
             )
 
-            Behavior on opacity { HNumberAnimation {} }
+            Behavior on opacity { HOpacityAnimator {} }
             Behavior on color { HColorAnimation {} }
 
             HoverHandler { id: overlayHover }
diff --git a/src/qml/Pages/AddChat/CreateRoom.qml b/src/qml/Pages/AddChat/CreateRoom.qml
index e375b576..e2141a6f 100644
--- a/src/qml/Pages/AddChat/CreateRoom.qml
+++ b/src/qml/Pages/AddChat/CreateRoom.qml
@@ -67,7 +67,7 @@ HBox {
             opacity: nameField.text ? 0 : 1
             visible: opacity > 0
 
-            Behavior on opacity { HNumberAnimation {} }
+            Behavior on opacity { HOpacityAnimator {} }
         }
     }
 
diff --git a/src/qml/SidePane/AccountDelegate.qml b/src/qml/SidePane/AccountDelegate.qml
index 92c94176..8c1e4e6b 100644
--- a/src/qml/SidePane/AccountDelegate.qml
+++ b/src/qml/SidePane/AccountDelegate.qml
@@ -20,7 +20,7 @@ HTileDelegate {
         ! sidePaneList.activateLimiter.running && ! sidePane.hasFocus
 
 
-    Behavior on opacity { HNumberAnimation {} }
+    Behavior on opacity { HOpacityAnimator {} }
 
 
     property bool disconnecting: false
@@ -74,7 +74,7 @@ HTileDelegate {
 
         Layout.fillHeight: true
 
-        Behavior on opacity { HNumberAnimation {} }
+        Behavior on opacity { HOpacityAnimator {} }
     }
 
     HButton {
@@ -102,7 +102,7 @@ HTileDelegate {
             Behavior on angle { HNumberAnimation {} }
         }
 
-        Behavior on opacity { HNumberAnimation {} }
+        Behavior on opacity { HOpacityAnimator {} }
     }
 
     contextMenu: HMenu {
diff --git a/src/qml/SidePane/RoomDelegate.qml b/src/qml/SidePane/RoomDelegate.qml
index 510ddd30..64545160 100644
--- a/src/qml/SidePane/RoomDelegate.qml
+++ b/src/qml/SidePane/RoomDelegate.qml
@@ -18,7 +18,7 @@ HTileDelegate {
         ! sidePaneList.activateLimiter.running && ! sidePane.hasFocus
 
 
-    Behavior on opacity { HNumberAnimation {} }
+    Behavior on opacity { HOpacityAnimator {} }
 
 
     readonly property bool invited: model.data.inviter_id && ! model.data.left