tdf#143114 Avoid StartDrag on TreeListBox when CaptureOnButton

The original method SvTreeListBox::StartDrag always triggers
a MouseButtonUp event and tries to initiate a Drag of a Line of
a TreeListBox (on MouseMove, btw).

This is not wanted if the last MouseButtonDown started a
ButtonActive mode and activated CaptureMouse, prepared to
trigger Action on that Button on MouseButtonUp. It leads to
unwanted/strange behaviour of Buttons/CheckBoxes when used in
TreeListBoxes.

The behaviour is also dependent on the UI implementation used
under Linux (gen/gtk3_kde5/gtk3/qt5/kf5) which are all
(unfortunately) behaving differently, but a first suggestion/
step to enhance the situation.

Found now for gen/qt5/kf5 that when on the LineEntry, but
not on the CheckBox, on MouseButtonUp the other line gets
switched. Corrected that.

Note: for gtk3_kde5/gtk3 there remains the problem that the
CheckBoxes get switched on MouseButtonDown, butt these are
generic widgets and this needs to be solved differently.

Change-Id: If4cfe894b716185293beff64fc7e482d6f6313d3
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/119644
Tested-by: Jenkins
Reviewed-by: Armin Le Grand <Armin.Le.Grand@me.com>

3 files changed, 27 insertions, 7 deletions

diff --git a/vcl/inc/svimpbox.hxx b/vcl/inc/svimpbox.hxx
index 554c5a8070ae..c46003c35dd4 100644
--- a/vcl/inc/svimpbox.hxx
+++ b/vcl/inc/svimpbox.hxx
@@ -310,8 +310,17 @@ public:
 
     bool                IsSelectable( const SvTreeListEntry* pEntry );
     void                SetForceMakeVisible(bool bEnable) { mbForceMakeVisible = bEnable; }
+
+    // tdf#143114 allow to ask if CaptureOnButton is active
+    // (MouseButtonDown hit on SvLBoxButton, CaptureMouse() active)
+    bool                IsCaptureOnButtonActive() const;
 };
 
+inline bool SvImpLBox::IsCaptureOnButtonActive() const
+{
+    return nullptr != m_pActiveButton && nullptr != m_pActiveEntry;
+}
+
 inline Image& SvImpLBox::implGetImageLocation( const ImageType _eType )
 {
     return m_aNodeAndEntryImages[_eType];
diff --git a/vcl/source/treelist/svimpbox.cxx b/vcl/source/treelist/svimpbox.cxx
index 835ee2eac949..0b4f1e50d122 100644
--- a/vcl/source/treelist/svimpbox.cxx
+++ b/vcl/source/treelist/svimpbox.cxx
@@ -1794,7 +1794,6 @@ void SvImpLBox::EntryInserted( SvTreeListEntry* pEntry )
 
 
 // ****** Control the control animation
-
 bool SvImpLBox::ButtonDownCheckCtrl(const MouseEvent& rMEvt, SvTreeListEntry* pEntry)
 {
     SvLBoxItem* pItem = m_pView->GetItem(pEntry,rMEvt.GetPosPixel().X(),&m_pActiveTab);
diff --git a/vcl/source/treelist/treelistbox.cxx b/vcl/source/treelist/treelistbox.cxx
index 278f42dde1c2..2338292820e9 100644
--- a/vcl/source/treelist/treelistbox.cxx
+++ b/vcl/source/treelist/treelistbox.cxx
@@ -1108,9 +1108,13 @@ void SvTreeListBox::SetupDragOrigin()
 
 void SvTreeListBox::StartDrag( sal_Int8, const Point& rPosPixel )
 {
-    Point aEventPos( rPosPixel );
-    MouseEvent aMouseEvt( aEventPos, 1, MouseEventModifiers::SELECT, MOUSE_LEFT );
-    MouseButtonUp( aMouseEvt );
+    if(nullptr != pImpl)
+    {
+        // tdf#143114 do not start drag when a Button/Checkbox is in
+        // drag-before-ButtonUp mode (CaptureMouse() active)
+        if(pImpl->IsCaptureOnButtonActive())
+            return;
+    }
 
     nOldDragMode = GetDragDropMode();
     if ( nOldDragMode == DragDropMode::NONE )
@@ -2282,18 +2286,26 @@ void SvTreeListBox::Paint(vcl::RenderContext& rRenderContext, const tools::Recta
 
 void SvTreeListBox::MouseButtonDown( const MouseEvent& rMEvt )
 {
-    pImpl->m_pCursorOld = pImpl->m_pCursor;
     pImpl->MouseButtonDown( rMEvt );
+
+    // tdf#143114 remember the *correct* starting entry
+    pImpl->m_pCursorOld = (rMEvt.IsLeft() && (nTreeFlags & SvTreeFlags::CHKBTN) && mnClicksToToggle > 0)
+        ? GetEntry(rMEvt.GetPosPixel())
+        : nullptr;
 }
 
 void SvTreeListBox::MouseButtonUp( const MouseEvent& rMEvt )
 {
     // tdf#116675 clicking on an entry should toggle its checkbox
-    if (rMEvt.IsLeft() && (nTreeFlags & SvTreeFlags::CHKBTN) && mnClicksToToggle > 0)
+    // tdf#143114 use the already created starting entry and if it exists
+    if (nullptr != pImpl->m_pCursorOld)
     {
         const Point aPnt = rMEvt.GetPosPixel();
         SvTreeListEntry* pEntry = GetEntry(aPnt);
-        if (pEntry && pEntry->m_Items.size() > 0 && (mnClicksToToggle == 1 || pEntry == pImpl->m_pCursorOld))
+
+        // compare if MouseButtonUp *is* on the same entry, regardless of scrolling
+        // or other things
+        if (pEntry && pEntry->m_Items.size() > 0 && 1 == mnClicksToToggle && pEntry == pImpl->m_pCursorOld)
         {
             SvLBoxItem* pItem = GetItem(pEntry, aPnt.X());
             // if the checkbox button was clicked, that will be toggled later, do not toggle here