gui: fix condition handling for lists

Base class must be called first, otherwise the condition can never
again become true. Fixes font size switching in Material theme.

Change-Id: I160a733549495e1bde3cead56b0a3582f0dc744c
diff --git a/gui/listbox.cpp b/gui/listbox.cpp
index 89a2c03..37ba958 100644
--- a/gui/listbox.cpp
+++ b/gui/listbox.cpp
@@ -122,11 +122,11 @@
 
 int GUIListBox::NotifyVarChange(const std::string& varName, const std::string& value)
 {
+	GUIScrollList::NotifyVarChange(varName, value);
+
 	if(!isConditionTrue())
 		return 0;
 
-	GUIScrollList::NotifyVarChange(varName, value);
-
 	// Check to see if the variable that we are using to store the list selected value has been updated
 	if (varName == mVariable) {
 		int i, listSize = mList.size();