Smooth Scrolling in a Table View for Custom Shortcuts
NSTableView comes with a couple of default shortcuts in an override of its keyDown(with:) method. These aren’t mentioned anywhere, so Xcode’s documentation quick help will repeat the NSView docstring to you, saying: The receiver can interpret event itself, or pass it to the system input manager using interpretKeyEvents(_:). The default implementation simply passes this message to the next responder. [Emphasis mine]
Synchronize Scrolling of Two (or More) NSScrollViews
You can make two NSScrollViews scroll in concert quite easily because every scrolled pixel is broadcasted to interested parties. In TableFlip, the main table is a NSTableView contained in a NSScrollView. You can view and hide row numbers in TableFlip; but I didn’t want to reload the whole table and mess with the table model to insert and remove the first column. Instead, I use a second table view with a single column. The upside of this approach: I can animate hiding the whole scroll view with the row numbers inside easily without affecting the main table.