Since Shift + L is already used by the Lock function, so extended Pick Linked doesn't work, therefore has U (and shift+U) been assigned to Pick Linked(+extend), so it will be possible to pick linked extended.

As there is no information about this function anywhere, it has been added to the menu like this: Select > Linked > Pick

NB. in order to work properly from the menu, the Pick Linked operator would need to have a 'wait for input' option, which I'm not able to add.