Sidebar: Correcting anomalous mouse behaviour while resizing

Currently, when the sidebar is showing, and we hold the handle to make
it wider/narrower, if we move the mouse much to the left (so that it
can't become any wider), and now move mouse pointer to the right (while
still holding the handle), it immediately begins to shrink.

Ideally how it should behave when we move the mouse much to the left is
that- the sidebar should begin shrinking once we have the mouse pointer
over the handle again and not immediately.

Change-Id: Id17dc19e6e1ad02fb7879ace9a2e092ac0128693

1 files changed, 13 insertions, 4 deletions

diff --git a/vcl/source/window/splitwin.cxx b/vcl/source/window/splitwin.cxx
index 232218957c61..e9286bdf2b0f 100644
--- a/vcl/source/window/splitwin.cxx
+++ b/vcl/source/window/splitwin.cxx
@@ -2542,21 +2542,30 @@ void SplitWindow::Tracking( const TrackingEvent& rTEvt )
         {
             sal_Bool    bPropSmaller = (mnMouseModifier & KEY_SHIFT) ? sal_True : sal_False;
             sal_Bool    bPropGreater = (mnMouseModifier & KEY_MOD1) ? sal_True : sal_False;
-            long    nDelta = mnMSplitPos-mnMStartPos;
 
             if ( (mnSplitTest & SPLIT_WINDOW) && !mpMainSet->mpItems )
             {
+                // nDelta corresponds to the direction to which user drags the mouse.
+                // If nDelta > 0, means user has dragged the handle towards the right and vice-versa
+                long nDelta = mnMSplitPos-mnMStartPos;
+
                 if ( (mpSplitSet == mpMainSet) && mbBottomRight )
                     nDelta *= -1;
                 ImplSetWindowSize( nDelta );
             }
             else
             {
-                long nNewSize = mpSplitSet->mpItems[mnSplitPos].mnPixSize;
+                long nNewSize( 0 );
+
+                // where is the sidebar is attached?
                 if ( (mpSplitSet == mpMainSet) && mbBottomRight )
-                    nNewSize -= nDelta;
+                    nNewSize = mnMaxSize - mnMStartPos; // right hand side of the screen
                 else
-                    nNewSize += nDelta;
+                    nNewSize = mnMStartPos; // left hand side of the screen
+
+                // do not make the sidebar wider than mnMaxSize
+                nNewSize = std::min(nNewSize, mpSplitSet->mpItems[mnSplitPos].mnMaxSize);
+
                 SplitItem( mpSplitSet->mpItems[mnSplitPos].mnId, nNewSize,
                            bPropSmaller, bPropGreater );
             }