Comfortable, Mouse-Only Tile Editing

Problem:

• Having to constantly switch between brush and eraser can be tiresome, if not detrimental for hand-disabled users.
• It would be great to have a way to delete tiles while still in brush mode -- most pixel editing apps will feature a right-click or middle-click to erase, for instance.

Suggestion 1:

• Make a checkbox on preferences that makes the wheel-click delete tile/object instead of "HAND" tool.
  This way, most users will keep working the way it is, while disabled and other users can maximize their productivity.

Suggestion 2:

• Make it so that selecting an empty tile lets me place that empty tile over used tiles, effectively deleting it.
  This idea won't truly solve the problem but mitigate it. I would suggest implementing both.

Start by locating the brush, eraser, and HAND tool input handling, then inspect how preferences are defined and applied. Compare the two suggested interaction approaches and determine which behavior fits the editor; done means tiles or objects can be deleted without switching tools and the existing default behavior remains unaffected.