private void expandBlock(int dialogType) {
		MemoryBlock block = getSelectedBlock();
		if (block == null) {
			return;
		}

		// Check for expansion of FileBytes use
		List<MemoryBlockSourceInfo> sourceInfos = block.getSourceInfos();
		int sourceIndex = dialogType == ExpandBlockDialog.EXPAND_UP ? 0 : (sourceInfos.size() - 1);
		MemoryBlockSourceInfo sourceInfo = sourceInfos.get(sourceIndex);
		if (sourceInfo.getFileBytes().isPresent()) {
			int choice = OptionDialog.showOptionDialogWithCancelAsDefaultButton(getComponent(),
				"Expanding File Bytes Block",
				"Block use of File Bytes will be expanded with a 0-filled region.  Continue?",
				"Continue...");
			if (choice != OptionDialog.OPTION_ONE) {
				return;
			}
		}

		showExpandBlockDialog(dialogType, block);
	}
Pop up a dialog to expand the block either up or down; "up" means make a
block have a lesser starting address; "down" means to make the block have
a greater ending address.

@param dialogType either ExpandBlockDialog.EXPAND_UP or
           ExpandBlockDialog.EXPAND_DOWN.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/memory/MemoryMapProvider.java