question

Hey @Borja Lorenzo, sorry for the delay in getting back to you. There are few ways I have found that can help you better visualize things in the GUI Builder.

First, you can always separate/group together controls using a groupbox or a panel. Both allow you to create boxes in whatever size you want and include other controls inside those boxes. The groupbox is pretty simple and the panel allows for more customization. You can see some information about both controls in the documentation about GUIs in the Additional View Attributes Reference section.

One of the customizations for panels is the color attribute. You can see how to use this attribute in the Panel section of the above link.

Also in the above link, under the General Attributes section, it says you can use the color attribute for Windows Common Controls to define the text color of the control. The Windows Common Controls are identified near the top of the page.

And while not as elegant, you can always extend your text boxes so they reach their corresponding button and then add text like a dash (-) or underline (_) to form a makeshift line between the text and button.