improve cursor location when popping forms

[daviortega]

when you click on something like change branch length, the cursor should be already there for the user to just type, in contrast with the current situation where the user must click in the form to input the new branch length.

In the case of branch length, the solution is to add branchWidthFrom.focus after the document.body.appendChild(branchWidthForm).

We just need to do the other ones.