Suppress control-click context menu, gwt 1.6 - gwt

Question

My gwt 1.6 application intercepts mouse clicks on hyperlinks, so when a user shift-clicks on links to "authors" they get an Edit... dialog box instead of navigating to the author's page. That's working nicely.
I'd now like to allow the user to control-click to select more than one author, but I can't figure out how to suppress the browser's default popup menu. This code handles shift-clicks correctly, but fails in the hosted browser when I control-click and half-fails in Firefox (handleCtrlClick() gets called, but I still get the browser menu):
public void onModuleLoad() {
Event.addNativePreviewHandler(this);
}
//
// Preview events-- look for shift-clicks on paper/author links, and pops up
// edit dialog boxes.
// And looks for control-click to do multiple selection.
//
public void onPreviewNativeEvent(Event.NativePreviewEvent pe) {
NativeEvent e = pe.getNativeEvent();
switch (Event.getTypeInt(e.getType())) {
case Event.ONCLICK:
if (e.getShiftKey()) { handleShiftClick(e); }
if (e.getCtrlKey()) { handleCtrlClick(e); }
break;
case Event.ONCONTEXTMENU:
if (e.getCtrlKey()) { // THIS IS NOT WORKING...
e.preventDefault();
e.stopPropagation();
}
break;
}
}
A breakpoint set inside the ONCONTEXTMENU case is never called.

Answer 1

IIRC ctrl + click is the correct way to select multiple items not ctrl + right click unless you're using a one button mouse (iMac), in that case I can't help you.
Could you provide more details?
Edit:
Why not override the contextmenu (e.g. disable it) then create your own context menu widget (perhaps based on vertical MenuBar + MenuItems) and display it only on Ctrl + RightClick?
In other words you'd create a MouseHandler somewhat like this (pseudo code):
public void onMouseDown(MouseDownEvent event) {
Widget sender = (Widget) event.getSource();
int button = event.getNativeButton();
if (button == NativeEvent.BUTTON_LEFT) {
if(event.is_ctrl_also)
{
// Add to selection
selection = selection + sender;
}
else
{
// Lose selection and start a new one
selection = sender;
}
}
else if(button == NativeEvent.BUTTON_RIGHT) {
if(event.is_ctrl_also)
{
// show context menu
this.contextmenu.show();
}
else
{
// do something else
}
}
return;
}
I've not encountered the bug with Ctrl-Leftclick firing a ContextMenu event, but I'm sure you could also make a workaround for Firefox only using permutations.

Answer 2

I'm getting closer:
public void onModuleLoad() {
Event.addNativePreviewHandler(this); // Catch shift- or control- clicks on links
addContextMenuEventListener(RootPanel.getBodyElement());
}
protected native void addContextMenuEventListener(Element elem) /-{
elem.oncontextmenu = function(e) {
return false; // TODO: only return false if control key down...
};
}-/;
That disables the right-click menu entirely; I'd really like to disable it ONLY if the control key is pressed...