diff --git a/libreplan-webapp/src/main/webapp/orders/_assignmentsBox.zul b/libreplan-webapp/src/main/webapp/orders/_assignmentsBox.zul
index be5e06b5a..5a1a7ddec 100644
--- a/libreplan-webapp/src/main/webapp/orders/_assignmentsBox.zul
+++ b/libreplan-webapp/src/main/webapp/orders/_assignmentsBox.zul
@@ -20,24 +20,22 @@
 -->
 
         <newdatasortablegrid id="gridMaterials"
-            fixedLayout="false"
-            model="@{assignedMaterialsController.assignedMaterials}" >
-            <columns>
-                <newdatasortablecolumn label="${i18n:_('Code')}" />
+            sizedByContent="true"
+            model="@{assignedMaterialsController.assignedMaterials}">
+            <columns width="100%">
+                <newdatasortablecolumn label="${i18n:_('Code')}" hflex="1" />
                 <newdatasortablecolumn label="${i18n:_('Receipt date')}" />
                 <newdatasortablecolumn label="${i18n:_('Units')}" />
                 <newdatasortablecolumn label="${i18n:_('Unit type')}" />
                 <newdatasortablecolumn label="${i18n:_('Unit price')}" />
                 <newdatasortablecolumn label="${i18n:_('Total price')}" />
-                <newdatasortablecolumn label="${i18n:_('Category')}" />
+                <newdatasortablecolumn label="${i18n:_('Category')}" hflex="1"/>
                 <newdatasortablecolumn label="${i18n:_('Status')}" />
                 <newdatasortablecolumn label="${i18n:_('Op.')}" />
             </columns>
             <rows>
                 <row self="@{each='assignedMaterial'}" value="@{assignedMaterial}">
-                    <textbox value="@{assignedMaterial.material.code}"
-                        constraint="no empty:${i18n:_('cannot be null or empty')}"
-                        readonly="true" />
+                    <label value="@{assignedMaterial.material.code}" hflex="true" />
                     <datebox value="@{assignedMaterial.estimatedAvailability}" />
                     <doublebox value="@{assignedMaterial.units}"
                         onChange="assignedMaterialsController.updateTotalPrice(self.parent)" />
@@ -48,7 +46,7 @@
                     <doublebox value="@{assignedMaterial.unitPrice}"
                         onChange="assignedMaterialsController.updateTotalPrice(self.parent)" />
                     <doublebox value="@{assignedMaterial.totalPrice}" disabled="${true}"/>
-                    <label value="@{assignedMaterial.material.category.name}" width="150px" />
+                    <label value="@{assignedMaterial.material.category.name}" />
                     <listbox mold="select" model="@{materialStatus}"
                         selectedItem="@{assignedMaterial.status}"
                         itemRenderer="org.libreplan.web.common.EnumsListitemRenderer" />
diff --git a/libreplan-webapp/src/main/webapp/orders/components/_listOrderElementMaterials.zul b/libreplan-webapp/src/main/webapp/orders/components/_listOrderElementMaterials.zul
index f4b0b4d6a..aae2671c8 100644
--- a/libreplan-webapp/src/main/webapp/orders/components/_listOrderElementMaterials.zul
+++ b/libreplan-webapp/src/main/webapp/orders/components/_listOrderElementMaterials.zul
@@ -74,15 +74,14 @@
 
             <tabpanel>
                 <!-- Material search -->
-                <hbox hflex="min">
+                <hbox width="100%" hflex="1">
                     <!-- Categories  -->
-                    <vbox>
+                    <vbox hflex="1">
                         <panel title="${i18n:_('Categories')}" border="normal">
                             <panelchildren>
                                 <toolbarbutton style="text-decoration: none" label="${i18n:_('Unselect')}"
                                     onClick="assignedMaterialsController.clearSelectionAllCategoriesTree()" />
-                                <tree id="allCategoriesTree"
-                                        width="280px" rows="10" vflex="true" multiple="false">
+                                <tree id="allCategoriesTree" rows="10" vflex="true" multiple="false">
                                     <treecols>
                                         <treecol label="Name" />
                                     </treecols>
@@ -91,7 +90,7 @@
                         </panel>
                     </vbox>
 
-                    <vbox hflex="min">
+                    <vbox hflex="1">
 
                         <!-- Found materials -->
                         <panel title="${i18n:_('Materials')}" border="normal">
@@ -111,10 +110,10 @@
                                 <listbox id="lbFoundMaterials"
                                     multiple="true"
                                     sizedByContent="true"
-                                    model="@{assignedMaterialsController.matchingMaterials}">
-                                    <listhead sizable="true">
+                                    model="@{assignedMaterialsController.matchingMaterials}" >
+                                    <listhead sizable="true" >
                                         <listheader label="${i18n:_('Code')}" />
-                                        <listheader label="${i18n:_('Name')}" />
+                                        <listheader label="${i18n:_('Name')}" hflex="1"/>
                                         <listheader label="${i18n:_('Unit type')}" />
                                         <listheader label="${i18n:_('Unit price')}" />
                                         <listheader label="${i18n:_('Category')}" />