Why can I no longer use this tool?

[Anonymous]

Why is this tool now always greyed out?

see attachment

I used to use it all the time
while using lines and geometry

If it is not needed, why is it still here?

[Barry Kelly]

It used to just be active when adjusting or drawing a new node and holding SHIFT to constrain the direction.

Now you have to hold the SHIFT button to constrain your movement and then press 'Q' to activate the tool.

Barry.

[NCornia]

That is a quirk indeed. I'll post it to the attention of the developers.

Best regards.