More improvements to drag tool selection disambiguation.

Fixes https://gitlab.com/kicad/code/kicad/issues/10745

(cherry picked from commit 2743fd583f)

pcbnew/tools/edit_tool.cpp

@@ -290,8 +290,11 @@ int EDIT_TOOL::Drag( const TOOL_EVENT& aEvent )
                 sTool->FilterCollectorForFreePads( aCollector );
                 sTool->FilterCollectorForHierarchy( aCollector, true );
 
-                // drop a knee between two segments to a single segment, or a via with two
-                // segments attached to the via
+                if( aCollector.GetCount() > 1 )
+                    sTool->GuessSelectionCandidates( aCollector, aPt );
+
+                // If we have a knee between two segments, or a via attached to two segments,
+                // then drop the selection to a single item.
                 static KICAD_T          trackTypes[] = { PCB_VIA_T, PCB_TRACE_T, PCB_ARC_T, EOT };
                 std::vector<PCB_TRACK*> tracks;
                 std::vector<PCB_TRACK*> vias;

pcbnew/tools/pcb_selection_tool.h

@@ -197,6 +197,8 @@ public:
 
     PCB_GROUP* GetEnteredGroup() { return m_enteredGroup; }
 
+    PCB_LAYER_ID GetActiveLayer() { return m_frame->GetActiveLayer(); }
+
     /**
      * In general we don't want to select both a parent and any of it's children.  This includes
      * both footprints and their items, and groups and their members.