Main issue in previous code was that you could not shift-alt-rmb select several contiguous strips, result was pretty much unusable. Also, enhanced general behavior of this selection mode, now (similar to alt-rm clicking on handles), when you alt-rmb click on a same strip several times, you alternate between: * Strip is selected, neighbor handles are selected; * Strip and its handles are selected, neighbor handles are selected. …which allows you to either grab or slide the strip. And refactored a bit code too, linked_handle has a complete different logic than without this option, simpler and clearer to completely separate them in code. Initial issue reported by Leon Cheung on IRC, thanks!