Init Footprint Viewer with current FPID.

Fixes: lp:1757421
* https://bugs.launchpad.net/kicad/+bug/1757421

eeschema/dialogs/dialog_edit_component_in_schematic.cpp

@@ -613,7 +613,7 @@ void DIALOG_EDIT_COMPONENT_IN_SCHEMATIC::showButtonHandler( wxCommandEvent& even
     else if( fieldNdx == FOOTPRINT )
     {
         // pick a footprint using the footprint picker.
-        wxString fpid;
+        wxString fpid = fieldValueTextCtrl->GetValue();
 
         KIWAY_PLAYER* frame = Kiway().Player( FRAME_PCB_MODULE_VIEWER_MODAL, true, this );
 

pcbnew/footprint_viewer_frame.cpp

@@ -622,6 +622,24 @@ void FOOTPRINT_VIEWER_FRAME::OnActivate( wxActivateEvent& event )
 }
 
 
+bool FOOTPRINT_VIEWER_FRAME::ShowModal( wxString* aFootprint, wxWindow* aResultantFocusWindow )
+{
+    if( aFootprint )
+    {
+        LIB_ID fpid( *aFootprint );
+        if( fpid.IsValid() )
+        {
+            setCurNickname( fpid.GetLibNickname() );
+            setCurFootprintName( fpid.GetLibItemName() );
+            ReCreateFootprintList();
+            SelectAndViewFootprint( NEW_PART );
+        }
+    }
+
+    return KIWAY_PLAYER::ShowModal( aFootprint, aResultantFocusWindow );
+}
+
+
 bool FOOTPRINT_VIEWER_FRAME::GeneralControl( wxDC* aDC, const wxPoint& aPosition, EDA_KEY aHotKey )
 {
     bool eventHandled = true;

pcbnew/footprint_viewer_frame.h

@@ -64,6 +64,15 @@ public:
      */
     void ReCreateLibraryList();
 
+    /**
+     * Function ShowModal
+     *
+     * Runs the Footprint Viewer as a modal dialog.
+     * @param aFootprint an optional FPID string to initialize the viewer with and to
+     *                   return a selected footprint through.
+     */
+    bool ShowModal( wxString* aFootprint, wxWindow* aResultantFocusWindow ) override;
+
 private:
 
     wxListBox*          m_libList;               // The list of libs names