# HG changeset patch
# Date 1363331396 0
# User sbr <sebastien@brissaud.name>
# Parent 53b8a32c40afdf60919bd681abec011b7d54d2d4
When opening the BuildObjectWindow, ensure the selected object class is visible in the class selector.

diff --git a/src/object_gui.cpp b/src/object_gui.cpp
--- a/src/object_gui.cpp
+++ b/src/object_gui.cpp
@@ -34,6 +34,19 @@
 	int info_height;                    ///< The height of the info box.
 	Scrollbar *vscroll;                 ///< The scrollbar.
 
+	/**
+	 * Scrolls \c WID_BO_CLASS_LIST so that the selected object class is visible
+	 */
+	void EnsureSelectedObjectClassIsVisible()
+	{
+		uint pos = 0;
+		for (int i = 0; i < _selected_object_class; i++) {
+			if (ObjectClass::Get((ObjectClassID) i)->GetUISpecCount() == 0) continue;
+			pos++;
+		}
+		this->vscroll->ScrollTowards(pos);
+	}
+
 public:
 	BuildObjectWindow(const WindowDesc *desc, Window *w) : PickerWindowBase(w), info_height(1)
 	{
@@ -48,6 +61,7 @@
 
 		this->SelectFirstAvailableObject(true);
 		assert(ObjectClass::Get(_selected_object_class)->GetUISpecCount() > 0); // object GUI should be disables elsewise
+		this->EnsureSelectedObjectClassIsVisible();
 		this->GetWidget<NWidgetMatrix>(WID_BO_OBJECT_MATRIX)->SetCount(4);
 
 		NWidgetMatrix *matrix = this->GetWidget<NWidgetMatrix>(WID_BO_SELECT_MATRIX);