Edit widgets and preview changes in Theme Customizer, with a control for each widget form in sections added for each sidebar rendered in the preview.
Before any changes have been made; widgets appear in sections corresponding to their assigned sidebars
After a change is made, the widget's Apply button is pressed to then see changes in preview and so changes can be published
Widgets can be added in sidebar sections; widgets get added to the top, and can be dragged into the desired location
Widgets can be trashed while in customizer, causing them to be moved to the Inactive Widgets sidebar
Widgets are be rearranged by drag-and-drop, and widgets can be assigned to other sidebars by dragging them over
Browse available widgets to add via a panel that slides out
I DON'T ALWAYS TEST MY WORDPRESS WIDGETS IN PRODUCTION, BUT WHEN I DO I USE THE WIDGET CUSTOMIZER PLUGIN