OK, I have an HTML file open and being edited, I use Ctrl-F12 to display Active Preview ... and it appears below, but I have 3 monitors so I want to make HTML Kit wider, over 2 screens, and move Active Preview to the right.
Can I do this?
Found it Classic Mode.
Classic Mode would work but let me also suggest Extended Preview for these reasons:
Classic Mode is limited to a single preview window. With Extended Preview you can open one, two or any number of windows on multiple monitors. Or arrange them as split windows on a single monitor.
Test for a variety of resolutions and conditions. One preview could be at full width to test for desktops. Another could be narrowed down to 320 pixels or so to test for small mobile screens. Yet another could turn off images or style sheets.
Preview in various browsers at the same time.
Preview on mobile devices like phones and tablets.
Preview through Windows, macOS, Linux and other platforms. These can be physical computers or virtual machines.
Whatever the combination, all your previews update with HTML-Kit Tools without having to manually reload one by one.
Extended Preview drop-down is on the far end of the main menu: