Add tlistbox::set_row_active()...

...so we can activate and deactive a row in a listbox.

src/gui/widgets/listbox.cpp

@@ -505,6 +505,13 @@ bool tlistbox::select_row(const unsigned row, const bool select)
 	return true;
 }
 
+void tlistbox::set_row_active(const unsigned row, const bool active)
+{
+	assert(row < get_item_count());
+	assert(rows_[row].grid());
+	rows_[row].grid()->set_active(active);
+}
+
 tlistbox::trow::trow(const tbuilder_grid& list_builder_,const t_string& label) :
 	grid_(dynamic_cast<tgrid*>(list_builder_.build())),
 	height_(0),

src/gui/widgets/listbox.hpp

@@ -122,6 +122,16 @@ public:
 
 	unsigned get_selected_row() const { return selected_row_; }
 
+	/** 
+	 * Makes a row active or inactive.
+	 *
+	 * NOTE this doesn't change the select status of the row.
+	 *
+	 * @param row                 The row to (de)activate.
+	 * @param select              true activate, false deactivate.
+	 */
+	void set_row_active(const unsigned row, const bool active);
+
 private:
 
 	/**