I'd swear this used to be a widespread feature, but now I can't find any evidence of it. A table cell contains information that is too wide for the column, so it is displayed in truncated form, and when the mouse is over the cell, a wide box appeared overlaying the table, similar to a tooltip but not a tooltip, to show more of the cell's content.

The thing that makes this fundamentally different from a tooltip is that the extendo-box (as I'm calling it until I hear a better name) would be positioned on top of the cell that it is giving information about, aligned so that the text you were able to see before is still in exactly the same position on the screen. You could just keep reading past the edge of the cell, instead of having to find your place again.

It's probably hard to understand from my description so here's a demo: http://jsfiddle.net/9z2xt/1/ ... try a mouseover on the table cells and watch how the text extends itself without moving.

I added one of these to a project under development, and although I replicated all the behavior I remember (as in the jsfiddle), it didn't turn out to be very helpful. I don't know what to do about alignment of the extended text when the cell is all the way on the right. I'm inclined to get rid of it. But the origin question is bothering me now.

Where did I get this idea from? Was it part of a common widget set like GTK, Qt, Motif? Is it still used in the current version of anything? Or did I really dream it up myself?


I finally spotted one in the wild, on a Windows box. It's in the Resource Monitor.

Resource Monitor screenshot showing an extendobox

  • I'm not familiar with the concept but it is interesting. I can imagine a number of good use cases for it. Thanks for sharing! Apr 17, 2014 at 20:23
  • Seen loads of implementations of this, wasn't aware that it had a special name. Before I might have said tooltip or hover, but from now on I will call it Extendo-box! :D
    – Franchesca
    Apr 17, 2014 at 21:19
  • something like this? cross-browser.com/toys/form_ta_autosize.html Apr 17, 2014 at 22:11
  • My first thought was tool-tip as well. Extendo-box isn't to bad! Maybe cell-extender
    – discorax
    Apr 22, 2014 at 21:25
  • On hover reveal, or On hover show more? It's kind of similar to tooltip behavior on links.
    – user43251
    May 22, 2014 at 8:11

3 Answers 3


You're right, it seems very familiar to me, as well. The closest example I can think of is simply how Excel behaves when my data cells are too narrow or short to display all the content. The content is displayed in what is labeled as the formula bar at the top right directly above the spreadsheet work area.

I'd write Janko at Warpspeed to see if he's familiar. He wrote the ultimate guide to table design patterns - patterns commonly used to solve the problems we have using data tables.



This is a pretty common practice but it doesn't really have a name or any kind of traditional "widget" associated with it. It's usually just referred to by its description, e.g. "show full cell contents on hover". If you were to ask somebody how to do it, you would ask, "how can I make my table show full cell contents on hover?"

I can't think of any table widgets off the top of my head that have that feature but I'm sure there are a few. Usually it's implemented by the application. I've implemented it in Java and Qt before just as tool-tips with explicit position, although if you wanted to go the extra mile you could certainly create a tool-tip-esque widget with a fancier look. It's usually a pretty trivial feature to add; for example, here is a discussion, along with about 15 lines of code, adding the feature to a QTableWidget in Qt.


The term that comes to mind for me is overflow, like the CSS property

I would say something like "cell overflow" or "overflow on hover"

Additionally: "popping out" or "surfacing" (cell) content(s)

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