tdf#95888 sw: make click to header area show header controls again

Regression from commit 54a2c8c0
(tdf#39080 Interactive hide-whitespace mode, 2015-08-30), the problem
was that SwPageFrm::IsOverHeaderFooterArea() checked if the header is
active before accepting that the user clicked in that area.

Don't require an active header at least in non-hide-whitespace mode, as
the member function is used in the "could there be a header here" sense
in SwEditWin::MouseButtonDown() to show the controls that allows
actually adding a header.

Change-Id: I6f905920113aed1512e333e718a8f26d88a3245d
(cherry picked from commit a23f85f1)

sw/source/core/layout/pagechg.cxx

@@ -2254,9 +2254,11 @@ bool SwPageFrm::IsOverHeaderFooterArea( const Point& rPt, FrameControlType &rCon
     SwRect aHeaderArea( Frm().TopLeft(),
            Size( Frm().Width(), nUpperLimit - Frm().Top() ) );
 
+    SwViewShell* pViewShell = getRootFrm()->GetCurrShell();
+    bool bHideWhitespaceMode = pViewShell->GetViewOptions()->IsHideWhitespaceMode();
     if ( aHeaderArea.IsInside( rPt ) )
     {
-        if (static_cast<const SwFrameFormat*>(GetRegisteredIn())->GetHeader().IsActive())
+        if (static_cast<const SwFrameFormat*>(GetRegisteredIn())->GetHeader().IsActive() || !bHideWhitespaceMode)
         {
             rControl = Header;
             return true;
@@ -2268,7 +2270,7 @@ bool SwPageFrm::IsOverHeaderFooterArea( const Point& rPt, FrameControlType &rCon
                 Size( Frm().Width(), Frm().Bottom() - nLowerLimit ) );
 
         if ( aFooterArea.IsInside( rPt ) &&
-             static_cast<const SwFrameFormat*>(GetRegisteredIn())->GetFooter().IsActive() )
+             (static_cast<const SwFrameFormat*>(GetRegisteredIn())->GetFooter().IsActive() || !bHideWhitespaceMode) )
         {
             rControl = Footer;
             return true;