     unless state.clickedLassoSegment then @clearLassoSelection()
 
     if state.consumedHitTest or state.suppressLassoSelect then return
+
+    # If it's not a left-click, pass.
+    if event.which isnt 1 then return
 
     # If the point was actually in the main canvas,
     # start a lasso select.

    # If someone else has already taken this click, pass.
    if state.consumedHitTest then return

    # Hit test against the tree.
    mainPoint = @trackerPointToMain(point)
    hitTestResult = @hitTest mainPoint, @tree

    # If someone else has already taken this click, pass.
    if state.consumedHitTest then return

    # If it's not a left-click, pass.
    if event.which isnt 1 then return

    # Hit test against floating blocks
    for record, i in @floatingBlocks
      hitTestResult = @hitTest @trackerPointToMain(point), record.block
