Fix: The reconfiguration window crashes on dropdown value changed

Initialization code to fix bug where the reconfiguration window crashes
when the dropdown value changes. The bug was related with trying to
re-add an existing key into a dictionary.

Author: nickkazepis

.gitattributes

@@ -0,0 +1,17 @@
+# Auto detect text files and perform LF normalization
+* text=auto
+
+# Custom for Visual Studio
+*.cs     diff=csharp
+
+# Standard to msysgit
+*.doc	 diff=astextplain
+*.DOC	 diff=astextplain
+*.docx diff=astextplain
+*.DOCX diff=astextplain
+*.dot  diff=astextplain
+*.DOT  diff=astextplain
+*.pdf  diff=astextplain
+*.PDF	 diff=astextplain
+*.rtf	 diff=astextplain
+*.RTF	 diff=astextplain

DynamicReconfigureSharp/DynamicReconfigureGroup.xaml.cs

@@ -81,6 +81,12 @@ public DynamicReconfigureGroup(Group g, Config def, Config min, Config max, stri
             _parent = g.parent;
             Loaded += (sender, args) =>
             {
+                paramsHolder.Children.Clear();
+                dropdowns.Clear();
+                checkboxes.Clear();
+                sliders.Clear();
+                boxes.Clear();
+
                 foreach (ParamDescription s in g.parameters)
                 {
                     string _name = s.name.data;