Pcbnew: Router tool should not block drag selection when idle

The other drawing tools allow drag selection while idle. Also, it makes
it more obvious to the user when accidentally drag selecting while
routing than just doing nothing on a drag with the routing tool selected
and idle.

pcbnew/router/router_tool.cpp

@@ -1243,6 +1243,12 @@ PNS::PNS_MODE ROUTER_TOOL::GetRouterMode()
 }
 
 
+bool ROUTER_TOOL::RoutingInProgress()
+{
+    return m_router->RoutingInProgress();
+}
+
+
 void ROUTER_TOOL::breakTrack()
 {
     if( m_startItem && m_startItem->OfKind( PNS::ITEM::SEGMENT_T ) )
@@ -1293,7 +1299,8 @@ int ROUTER_TOOL::MainLoop( const TOOL_EVENT& aEvent )
     // Main loop: keep receiving events
     while( TOOL_EVENT* evt = Wait() )
     {
-        setCursor();
+        if( !evt->IsDrag() )
+            setCursor();
 
         if( evt->IsCancelInteractive() )
         {

pcbnew/router/router_tool.h

@@ -48,6 +48,14 @@ public:
 
     PNS::PNS_MODE GetRouterMode();
 
+    /**
+     * @brief Returns whether routing is currently active.
+     *
+     * @return True if actively routing, false if not routing or
+     *         tool is activated and idle.
+     */
+    bool RoutingInProgress();
+
     void setTransitions() override;
 
     // A filter for narrowing a collection representing a simple corner

pcbnew/tools/pcb_selection_tool.cpp

@@ -258,7 +258,7 @@ int PCB_SELECTION_TOOL::Main( const TOOL_EVENT& aEvent )
         ROUTER_TOOL* router = m_toolMgr->GetTool<ROUTER_TOOL>();
 
         // If the router tool is active, don't override
-        if( router && router->IsToolActive() )
+        if( router && router->IsToolActive() && router->RoutingInProgress() )
         {
             evt->SetPassEvent();
         }