when I lasoo fields with select tool in base, though I see the marching ants as soon as I let go left mouse button the arrow is replaced by Capital I no green dots appear! Have I missed some setting, or is base faulty?
The answer is choosing the correct toolbar helps. I was being a newbie selecting the arrow from Form Design instead of Form Controls! Once i realised my mistake it works fine.
I guess that you might be trying to select a text box control while editing a form. If you include the box label in the select area, then both the label and the box are selected (green dots). If you only include the text box, then the select doesn’t work (as you describe, a “capital I”).
If you want to select just the box without the label try clicking on the box while holding down the Ctrl key (for Linux and Windows–not sure about Mac). In edit mode of course. Once selected, right-click inside the green arrows to open up the control dialog.