diff --git a/addons/hr_timesheet_invoice/hr_timesheet_invoice_view.xml b/addons/hr_timesheet_invoice/hr_timesheet_invoice_view.xml
index c18ac4de667..d9fb034885f 100644
--- a/addons/hr_timesheet_invoice/hr_timesheet_invoice_view.xml
+++ b/addons/hr_timesheet_invoice/hr_timesheet_invoice_view.xml
@@ -24,9 +24,9 @@
                 </group>
                 <xpath expr="/form/sheet" position='before'>
                     <header>
-                        <button name="set_pending" string="Pending" type="object" states="open"/>
-                        <button name="set_close" string="Close" type="object" states="open,pending"/>
-                        <button name="set_open" string="Re-open project" type="object" states="pending,cancelled,close,draft"/>
+                        <button name="set_pending" string="Pending" type="object" states="open" class="oe_form_button_active_flow"/>
+                        <button name="set_close" string="Close" type="object" states="open,pending" class="oe_form_button_active_flow"/>
+                        <button name="set_open" string="Re-open project" type="object" states="pending,cancelled,close,draft" class="oe_form_button_return_flow"/>
                         <button name="set_cancel" string="Cancel" type="object" states="open,pending"/>
                         <field name="state" readonly="1" widget="statusbar"
                             statusbar_visible="open,pending,close" statusbar_colors='{"pending":"red", "template":"blue"}'/>