--- /dev/null
+package jalview.api;
+
+/**
+ * Describes a visual container that can show two alignments.
+ *
+ * @author gmcarstairs
+ *
+ */
+public interface SplitContainerI
+{
+
+ /**
+ * Set visibility of the specified split view component.
+ *
+ * @param alignFrame
+ * @param show
+ */
+ // TODO need an interface for AlignFrame?
+ void setComplementVisible(Object alignFrame, boolean show);
+
+}