Since Citrus UI hides rulers by default (based on an old discussion on the OOo mailing list), I wanted to figure out some other way of presenting some of the functionality of the good ol’ ruler (like tab and paragraph alignment) to the user.
So… This shows up when a user puts the cursor at the borders of a tabbed space (by clicking or using the keyboard). If the user clicks on the tab symbol, he’ll get a drop-down menu of all the possible tabs (left, right, center, decimal), along with a “Reset this tab” button, which puts the tab in its default position (just like when you drag a tab symbol off the ruler). If the user drags the resize handle, the tab moves accordingly.
The same with the other types of tabs.
It works for columns too.
UPDATE: Here are a few other mockups of tabs in various situations.
UPDATE 2: I replaced the main mockup with one that shows more text and a cursor.
UPDATE 3: As Johannes Bausch suggested on the mailing list, dragging a tab’s resize handle should trigger the ruler. When finished dragging, the ruler should hide again.