[chronojump] Fixed exercise options label on changing mode

[Xavier de Blas <xaviblas src gnome org>]

commit cc05e4ff090b007eca47d6fabd8217afd3014c75
Author: Xavier de Blas <xaviblas gmail com>
Date:   Wed Apr 29 18:33:17 2020 +0200

    Fixed exercise options label on changing mode

 src/gui/app1/chronojump.cs | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/gui/app1/chronojump.cs b/src/gui/app1/chronojump.cs
index 6c4f7daa..80322e21 100644
--- a/src/gui/app1/chronojump.cs
+++ b/src/gui/app1/chronojump.cs
@@ -2871,6 +2871,9 @@ public partial class ChronoJumpWindow
                vbox_contacts_signal_comment.Visible = false;
                frame_jumps_automatic.Visible = false;
 
+               //blank exercise options: useful for changing from jumps or runs to forceSensor, runEncoder, 
reaction time, other
+               label_contacts_exercise_selected_options.Text = "";
+
                //on OSX R is not installed by default. Check if it's installed. Needed for encoder and force 
sensor
                if(
                                ( m == Constants.Menuitem_modes.POWERGRAVITATORY ||