Fix initial width of the color palette in welded picker

Problem can be seen with non-gtk3, if the initial
palette has no scrollbar (e.g. "standard" palette).

The cause is that in non-gtk3 we don't have overlay
scrollbars, so the palette area needs to be enlarged
when switching from a palette with a scrollbar to a
palette without a scrollbar. In practise, this was
happening also on initial show, although the palette
already had the correct width.

To fix that, start with a never scrollbar policy by
default, and add the scrollbar later if needed.

Change-Id: I5286f301b3c7ef5c72b650290ace784222f7922d
Reviewed-on: https://gerrit.libreoffice.org/56995Reviewed-by: Maxim Monastirsky <momonasmon@gmail.com>
Tested-by: Maxim Monastirsky <momonasmon@gmail.com>

svtools/source/control/valueset.cxx

@@ -3634,9 +3634,6 @@ Size SvtValueSet::CalcWindowSizePixel( const Size& rItemSize, sal_uInt16 nDesire
         aSize.AdjustHeight(nTxtHeight + n + mnSpacing );
     }
 
-    // sum possible ScrollBar width
-    aSize.AdjustWidth(GetScrollWidth());
-
     return aSize;
 }
 

svx/uiconfig/ui/colorwindow.ui

@@ -22,8 +22,6 @@
   </object>
   <object class="GtkPopover" id="palette_popup_window">
     <property name="can_focus">False</property>
-    <property name="hexpand">True</property>
-    <property name="vexpand">True</property>
     <property name="border_width">4</property>
     <property name="position">bottom</property>
     <property name="constrain_to">none</property>
@@ -106,6 +104,7 @@
             <property name="visible">True</property>
             <property name="can_focus">True</property>
             <property name="hscrollbar_policy">never</property>
+            <property name="vscrollbar_policy">never</property>
             <property name="shadow_type">in</property>
             <child>
               <object class="GtkViewport">