Final answer:
In an app development environment, the column that holds components for dragging onto the app screen is typically the left column, which contains a range of user interface elements.
Step-by-step explanation:
The Designer View's four columns in a typical app development environment includes a specific column with a palette of components you can drag onto your app's screen. This palette is commonly found in the left column. You can select various components, such as buttons, text fields, images, and other user interface elements from this column, and drag them onto your app's screen to build its layout and functionality.