Fixed ColorPrint Legend update if Print preset was changed and model was resliced.

src/slic3r/GUI/wxExtensions.hpp

@@ -720,7 +720,9 @@ public:
         const wxString& name = wxEmptyString);
     ~DoubleSlider() {}
 
-    // permissible error for layer height
+    /* For exporting GCode in GCodeWriter is used XYZF_NUM(val) = PRECISION(val, 3) for XYZ values. 
+     * So, let use same value as a permissible error for layer height.
+     */
     static double epsilon() { return 0.0011;}
 
     void    msw_rescale();