[chronojump] Fixed a crash on start software and clicking on encoder

[Xavier de Blas <xaviblas src gnome org>]

commit 9e9832e073f120cb721cf6421924e7681ef3d57e
Author: Xavier de Blas <xaviblas gmail com>
Date:   Fri Apr 3 13:47:38 2020 +0200

    Fixed a crash on start software and clicking on encoder

 src/gui/app1/encoder.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/gui/app1/encoder.cs b/src/gui/app1/encoder.cs
index 53fbd3b0..78a5dfde 100644
--- a/src/gui/app1/encoder.cs
+++ b/src/gui/app1/encoder.cs
@@ -5372,7 +5372,8 @@ public partial class ChronoJumpWindow
                                allocation.Height != encoder_capture_curves_allocationYOld) 
                {
                        encoder_capture_curves_bars_pixmap = new Gdk.Pixmap 
(encoder_capture_curves_bars_drawingarea.GdkWindow, allocation.Width, allocation.Height, -1);
-                       if(encoder_capture_curves_bars_pixmap == null || ! preferences.encoderCaptureInfinite 
|| firstSetOfCont)
+                       if(encoder_capture_curves_bars_pixmap == null || ! preferences.encoderCaptureInfinite 
|| firstSetOfCont ||
+                               encoderGraphDoPlot == null || ! encoderGraphDoPlot.GraphPrepared)
                        {
                                if(encoderGraphDoPlot == null || ! encoderGraphDoPlot.GraphPrepared)
                                {