Updated list:
Custom Formats no longer available. Workaround: Create a Custom Format in a Numbers 2 document. Save. Then Save As… a copy with a new name so Numbers 3 can't snaffle your original Numbers 2 document. Open the copy in Numbers 3 and the Custom formats will be listed in Format Inspector > Cell > Data Format. The Custom Formats are carried over and they work. Note: copying a custom formatted Cell or Table in Numbers 2, then pasting into Numbers 3 does not work. The Custom cell(s) are pasted as text.
I can't add a shadow to a Table. Workaround: insert a rectangle Shape, Arrange > Send To Back, slide it behind the Table. Use the Alignment Guides to drag and resize the rectangle. Numbers > Preferences > Rulers > Alignment Guides. Turn them on.
Sorting by multiple Columns has gone. Workaround: Add another Column (e.g. D) =A&B&C (or your preferred sort order for Columns). Sort by Column D.
No way to set margins. Workaround: Print the document as PDF. Open the PDF in Preview and use the Cropping Tool to crop out the white space.
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Show Print View and Show Layout have gone (update). Workaround hints:
Menu > View >Show Rulers. Drag Alignment Guides from a ruler to where you want them. Caution: the rulers and/or Alignment Guides may not be accurate. Try Format Inspector > Arrange > Position (or Size) to see if that works better for you.
Menu > Numbers > Preferences > Rulers > Alignment Guides. That allows you to align objects with *each other* (rather than with the ruler guides). These guides help to align objects left, middle, right, top, bottom.
Select multiple objects, then Format Inspector > Arrange > Align (or Distribute). Also under Menu > Arrange.
When duplicating an object (such as a nicely formatted Table that you want to reuse) select the Table, copy, and before you paste, click on the canvas below or beside. Pasted Table will automatically be aligned with the original.
Menu > File > Print to see the Print Preview. Use the Content Scale slider.
Also, see where you can delete blank rows or columns, or make columns narrower, or drag objects to reduce white space. Not as easy as editing in Print View in Numbers 2, but you are still responsible for (and in charge of) the final look!
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Reorganize panel has gone. How do I Sort selected rows? Workaround: copy those rows to a new table, sort, then copy and paste back.
Autocomplete has gone. Workaround: enter your most used values into a column. Select all body cells in that Column and change the Cell format to pop-up. The pop-up will now contain choices for filling in other Rows. Another workaround could be to use a lookup table of frequently used entries (each with a unique first character). Type the first character of an entry in one Column. The next Column fills in the full entry from a lookup table. After all, is this not how Autocomplete works?
Numbers 3.0 does not show dates in a Chart. Workaround: convert the dates to a Duration (day or week from the starting time) or even a number to represent time elapsed.
Regards,
Ian.