diff --git a/data/gui/gajim_themes_window.ui b/data/gui/gajim_themes_window.ui
index fbc921f39..184bf4727 100644
--- a/data/gui/gajim_themes_window.ui
+++ b/data/gui/gajim_themes_window.ui
@@ -65,6 +65,7 @@
                   <object class="GtkHButtonBox" id="hbuttonbox27">
                     <property name="visible">True</property>
                     <property name="spacing">6</property>
+                    <property name="layout_style">center</property>
                     <child>
                       <object class="GtkButton" id="add_button">
                         <property name="label">gtk-add</property>
@@ -149,7 +150,7 @@
                       </object>
                       <packing>
                         <property name="x_options">GTK_FILL</property>
-                        <property name="y_options"></property>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -166,7 +167,7 @@
                         <property name="top_attach">1</property>
                         <property name="bottom_attach">2</property>
                         <property name="x_options">GTK_FILL</property>
-                        <property name="y_options"></property>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -183,7 +184,7 @@
                         <property name="top_attach">2</property>
                         <property name="bottom_attach">3</property>
                         <property name="x_options">GTK_FILL</property>
-                        <property name="y_options"></property>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -198,7 +199,7 @@
                         <property name="top_attach">3</property>
                         <property name="bottom_attach">4</property>
                         <property name="x_options">GTK_FILL</property>
-                        <property name="y_options"></property>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -212,8 +213,8 @@
                       <packing>
                         <property name="left_attach">2</property>
                         <property name="right_attach">3</property>
-                        <property name="x_options"></property>
-                        <property name="y_options"></property>
+                        <property name="x_options"/>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -229,8 +230,8 @@
                         <property name="right_attach">3</property>
                         <property name="top_attach">1</property>
                         <property name="bottom_attach">2</property>
-                        <property name="x_options"></property>
-                        <property name="y_options"></property>
+                        <property name="x_options"/>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -248,7 +249,7 @@
                         <property name="right_attach">3</property>
                         <property name="top_attach">2</property>
                         <property name="bottom_attach">3</property>
-                        <property name="y_options"></property>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -270,8 +271,8 @@
                         <property name="right_attach">2</property>
                         <property name="top_attach">3</property>
                         <property name="bottom_attach">4</property>
-                        <property name="x_options"></property>
-                        <property name="y_options"></property>
+                        <property name="x_options"/>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -293,8 +294,8 @@
                         <property name="right_attach">3</property>
                         <property name="top_attach">3</property>
                         <property name="bottom_attach">4</property>
-                        <property name="x_options"></property>
-                        <property name="y_options"></property>
+                        <property name="x_options"/>
+                        <property name="y_options"/>
                       </packing>
                     </child>
                     <child>
@@ -349,7 +350,7 @@
                     <property name="top_attach">4</property>
                     <property name="bottom_attach">5</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -365,7 +366,7 @@
                     <property name="top_attach">4</property>
                     <property name="bottom_attach">5</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -381,7 +382,7 @@
                     <property name="top_attach">3</property>
                     <property name="bottom_attach">4</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -394,7 +395,7 @@
                     <property name="top_attach">3</property>
                     <property name="bottom_attach">4</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -407,7 +408,7 @@
                     <property name="top_attach">2</property>
                     <property name="bottom_attach">3</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -423,7 +424,7 @@
                     <property name="top_attach">2</property>
                     <property name="bottom_attach">3</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -436,7 +437,7 @@
                   <packing>
                     <property name="right_attach">2</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -449,7 +450,7 @@
                     <property name="top_attach">5</property>
                     <property name="bottom_attach">6</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -465,7 +466,7 @@
                     <property name="top_attach">5</property>
                     <property name="bottom_attach">6</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -479,7 +480,7 @@ Messages</property>
                     <property name="top_attach">7</property>
                     <property name="bottom_attach">8</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -495,7 +496,7 @@ Messages</property>
                     <property name="top_attach">7</property>
                     <property name="bottom_attach">8</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -521,7 +522,7 @@ Messages</property>
                     <property name="top_attach">8</property>
                     <property name="bottom_attach">9</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>
@@ -537,7 +538,7 @@ Messages</property>
                     <property name="top_attach">8</property>
                     <property name="bottom_attach">9</property>
                     <property name="x_options">GTK_FILL</property>
-                    <property name="y_options"></property>
+                    <property name="y_options"/>
                   </packing>
                 </child>
                 <child>