On a multi-select tree control, two slow single-clicks grab selected node

We recently switched to using multiple select on a tree control in our product, and (on Windows, at least) now have the problem that if you select a node, wait a moment, then select the node again, then that node starts dragging (cursor changes to pointing finger). The same behavior happens if you right-click on a node to bring up a context menu, then left-click on the node (i.e. to the left of the menu). Is there anyway to turn off this auto-drag behavior?

Here is the __init__ call for our tree:

        wx.TreeCtrl.__init__(self, parent, -1, style=wx.TR_MULTIPLE|wx.TR_HAS_BUTTONS|wx.TR_HIDE_ROOT|wx.TR_DEFAULT_STYLE)

Thanks,
Matt