private boolean isRecentlyUsedDataType(DataType dataType) {
		return (recentlyUsedDataType != null && recentlyUsedDataType.equals(dataType));
	}
Data type was removed, so remove it is no longer a recently used.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/datamgr/DataTypePropertyManager.java