fix: context menu does not appear at right-click on a tree node text

Refs #2069

Author: ansgarbecker

source/apphelpers.pas

@@ -1528,7 +1528,7 @@ procedure FixVT(VT: TVirtualStringTree; IsResultGrid: Boolean=False);
   VT.OnEndOperation := Mainform.AnyGridEndOperation;
   VT.BorderStyle := bsNone; // Cosmetic
   // Some trees have their own OnContextMenu logic set at design time:
-  if not Assigned(VT.OnContextPopup) then
+  if (not Assigned(VT.OnContextPopup)) and Assigned(VT.Header.PopupMenu) then
     VT.OnContextPopup := MainForm.AnyGridContextPopup;
 end;
 

source/main.lfm

@@ -951,7 +951,6 @@ object MainForm: TMainForm
         Constraints.MinHeight = 32
         Constraints.MinWidth = 32
         DefaultText = 'Node'
-        DragMode = dmAutomatic
         DragType = dtVCL
         Header.AutoSizeIndex = 0
         Header.Columns = <        
@@ -993,6 +992,7 @@ object MainForm: TMainForm
         OnGetNodeDataSize = DBtreeGetNodeDataSize
         OnInitChildren = DBtreeInitChildren
         OnInitNode = DBtreeInitNode
+        OnMouseMove = DBtreeMouseMove
         OnMouseUp = DBtreeMouseUp
       end
     end

source/main.pas

@@ -841,6 +841,8 @@   TMainForm = class(TExtForm)
       var Handled: Boolean);
     procedure DataGridContextPopup(Sender: TObject; MousePos: TPoint;
       var Handled: Boolean);
+    procedure DBtreeMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer
+      );
     procedure FormActivate(Sender: TObject);
     procedure ImageListGetWidthForPPI(Sender: TCustomImageList;
       AImageWidth, APPI: Integer; var AResultWidth: Integer);
@@ -4599,6 +4601,16 @@ procedure TMainForm.DataGridContextPopup(Sender: TObject; MousePos: TPoint;
   Handled := Tree.Header.InHeader(MousePos);
 end;
 
+procedure TMainForm.DBtreeMouseMove(Sender: TObject; Shift: TShiftState; X,
+  Y: Integer);
+begin
+  // Required step with DragMode=dmManual
+  // We use dmManual to fix a non appearing context menu in conjunction with DragType=dtVCL
+  // This reserves left-clicks for dragging, leaving right-clicks for context menu
+  if (ssLeft in Shift) and (not DBtree.Dragging) then
+    DBtree.BeginDrag(False);
+end;
+
 procedure TMainForm.FormActivate(Sender: TObject);
 begin
   // Work around non-working wsMaxmized in OnCreate and OnShow