Lakewalker creates duplicate ways

[avarab@…]

The Lakewalker plugin will create duplicate ways when tracing lakes occasionally. Just I had to trace ~30 lakes before running into this bug and recently fixed up a bunch of lakes in Iceland that were duplicates, sometimes as many as 6 identical lakes sharing the same nodes.

[Daeron]

This happens if you activate the Lakewalker more than once without tracing anything. It seems activating it "creates" new Lakewalker, and then when you click somewhere, all the Lakewalkers get the signal and trace from the same spot, resulting in duplicated ways.

[stoecker]

In [o18825].

I could not reliable reproduce it, but I prevented double calling now.