If you want to use the enqueue botton in LW, you have to have LW set to use the LW player. If you changed it to use a different player then you won't be able to enqueue songs in LW.

In LW go to Tools > Options > Player, tick the box to use LW player, then click apply. But remember that the LW player is not the best and the quality of the songs will probably suffer.

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