Pcbnew: fix a crash when aborting a pad move or drag in board editor

Documentation/compiling/COMPILING.txt

@@ -69,17 +69,6 @@ files in /mingw/include and library link files in /mingw/lib.  You can install
 path by setting --prefix=/mingw to configure above to change where "make install"
 puts everything.  We will refer to the --prefix setting as <wxInstallDir> below.
 
-If you are planning to enable the USE_WX_GRAPHICS_CONTEXT option (see options
-section below) on Windows using MinGW/MSYS you must build wxWidgets with the
---enable-graphics_ctx switch added to the build configurations above.
-Unfortunately it is not quite that simple because MinGW does not define the
-Gdi+ header and link library files.  First you must download the required Gdi+
-development files from
-
-<http://www.miscdebris.net/blog/2009/09/17/adding-gdi-headers-to-mingw-to-compile-wxwidgets-with-wxgraphicscontext-support/>
-
-and unzip them where MinGW is installed.
-
 Verify that wx-config is in your path.  Modify your PATH environment variable
 if need be so you can run wx-config from a command prompt.  You may have to
 restart your msys shell, depending on how you modify your PATH.
@@ -210,13 +199,10 @@ These should be set from command line:
 
  KICAD_MINIZIP ON/OFF
 
- USE_WX_ZOOM ON/OFF (OPTIONAL)
-   Experimental coordinate translation code using wxDC instead of custom
-   Kicad version.
-
  USE_WX_GRAPHICS_CONTEXT ON/OFF (OPTIONAL)
-   Experimental advanced drawing library code using wxGraphicsContext.  It
-   requires wxWidgets to be built with the --enable-graphics_ctx switch.
+   *Experimental* advanced drawing library code using wxGraphicsContext (for tests only).
+   Under Windows, a very recent version of mingw is needed.
+   It requires wxWidgets to be built with the --enable-graphics_ctx switch.
    See building wxWidgets above.
 
 Note: that it is easy to build only a specific binary such as pcbnew alone:

pcbnew/move-drag_pads.cpp

@@ -22,7 +22,7 @@ static wxPoint Pad_OldPos;
 
 /* Cancel move pad command.
  */
-static void Exit_Move_Pad( EDA_DRAW_PANEL* Panel, wxDC* DC )
+static void Abort_Move_Pad( EDA_DRAW_PANEL* Panel, wxDC* DC )
 {
     D_PAD* pad = s_CurrentSelectedPad;
 
@@ -62,6 +62,9 @@ static void Show_Pad_Move( EDA_DRAW_PANEL* aPanel, wxDC* aDC, const wxPoint& aPo
     BASE_SCREEN* screen = aPanel->GetScreen();
     D_PAD*       pad    = s_CurrentSelectedPad;
 
+    if( pad == NULL )       // Should not occur
+        return;
+
     if( aErase )
         pad->Draw( aPanel, aDC, GR_XOR );
 
@@ -277,7 +280,7 @@ void WinEDA_BasePcbFrame::StartMovePad( D_PAD* Pad, wxDC* DC )
     s_CurrentSelectedPad = Pad;
     Pad_OldPos = Pad->m_Pos;
     Pad->DisplayInfo( this );
-    DrawPanel->SetMouseCapture( Show_Pad_Move, Exit_Move_Pad );
+    DrawPanel->SetMouseCapture( Show_Pad_Move, Abort_Move_Pad );
 
     /* Draw the pad  (SKETCH mode) */
     Pad->Draw( DrawPanel, DC, GR_XOR );