Modals / Pop-up windows / Dialog boxes

Thought: one of the main considerations for whether to have something as a no-other-actions pop-up (like PyCharm's "Settings" modal) or as part of the permanent UI (like PyCharm's "Project" sidebar) or as a other-actions-allowed pop-up (like Photoshop's various tool windows) is whether or not the user is likely to need to switch between the actions in that pop-up and the actions in some other part of the UI. A "save" or "load" action doesn't require interacting with the rest of the UI, so it can be in a pop-up that disables other actions.

Scrollbars

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