void clearSystemClipboard() {
		try {
			Clipboard systemClipboard = GClipboard.getSystemClipboard();
			if (!systemClipboard
					.isDataFlavorAvailable(ProgramTreeTransferable.localTreeNodeFlavor)) {
				return;
			}

			Object data = systemClipboard.getData(ProgramTreeTransferable.localTreeNodeFlavor);
			if (data == null) {
				return;
			}

			// we were the owner, so get rid of our data, so there is no unclaimed garbage
			doClearSystemClipboard(systemClipboard);
		}
		catch (Exception e) {
			// ignore errors
		}
	}
Clear the system clipboard if there is tree transferable data on it.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/ProgramTreeActionManager.java