SWTBot cannot copy/paste on tree items using keyboard shortcuts

Question

I want to copy/paste between two SWTBotTreeItem using CTRL+C/CTRL+V. Using copy/paste with the context menu works well, but I am required to use keyboard shortcuts too. The following code doesn't work: I can't copy the first node.

SWTBotTreeItem node1 = parentNode.getNode(name1);
SWTBotTreeItem node2 = parentNode.getNode(name2);
node1.select().pressShortcut(SWT.CTRL, 'C');
node2.select().pressShortcut(SWT.CTRL, 'V');

Even if I use 'copy' on node1 via the contextMenu, pressing CTRL+V on node2 does nothing.

I would like to understand what mistake I've done when using the pressShortcut.