Specific delete is a quick editing mode that lets you delete a single kind of element. It works a lot like Replace mode but only for deletion.

Usage

This is what specific delete looks like.

This is what Ctrl + Alt + Selection looks like.

1. Press Delete to toggle the mode. Your HUD should show a notification that it was enabled.
2. Ctrl + Alt + left-click an element to select it with a cyan surrounding rectangle. This is the element that will be deleted.
3. Left click on a desired area to delete all particles of that element under your brush.
4. Press Delete to exit specific deletion.

Here's a short gfy on how it's used.