Use qualified window names when searching for 3D viewers.

Just searching in children didn't work because the windows aren't
actually in the child window lists.

Fixes: lp:1831774
* https://bugs.launchpad.net/kicad/+bug/1831774

3d-viewer/3d_viewer/eda_3d_viewer.cpp

@@ -158,7 +158,7 @@ EDA_3D_VIEWER::EDA_3D_VIEWER( KIWAY *aKiway, PCB_BASE_FRAME *aParent,
                 KIWAY_PLAYER( aKiway, aParent,
                               FRAME_PCB_DISPLAY3D, aTitle,
                               wxDefaultPosition, wxDefaultSize,
-                              style, VIEWER3D_FRAMENAME )
+                              style, QUALIFIED_VIEWER3D_FRAMENAME( aParent ) )
 {
     wxLogTrace( m_logTrace, "EDA_3D_VIEWER::EDA_3D_VIEWER %s", aTitle );
 

3d-viewer/3d_viewer/eda_3d_viewer.h

@@ -47,6 +47,8 @@
 #define KICAD_DEFAULT_3D_DRAWFRAME_STYLE    (wxDEFAULT_FRAME_STYLE | wxWANTS_CHARS)
 
 #define VIEWER3D_FRAMENAME wxT( "Viewer3DFrameName" )
+#define QUALIFIED_VIEWER3D_FRAMENAME( parent ) \
+                    ( wxString( VIEWER3D_FRAMENAME ) + wxT( ":" ) + parent->GetName() )
 
 /**
  *  Create and handle a window for the 3d viewer connected to a Kiway and a pcbboard

pcbnew/pcb_base_frame.cpp

@@ -114,7 +114,7 @@ PCB_BASE_FRAME::~PCB_BASE_FRAME()
 
 EDA_3D_VIEWER* PCB_BASE_FRAME::Get3DViewerFrame()
 {
-    return dynamic_cast<EDA_3D_VIEWER*>( FindWindow( VIEWER3D_FRAMENAME ) );
+    return dynamic_cast<EDA_3D_VIEWER*>( FindWindowByName( QUALIFIED_VIEWER3D_FRAMENAME( this ) ) );
 }