Grids of dynamic objects responding to mouseovers seem to be quite slow in general, for instance:

  Mouseover[Framed[" ", Background -> Blue], 
   Framed[" ", Background -> White]], {i, 50}, {j, 50}], 
 Spacings -> {0, 0}]

How can this lagging be avoided?

  • $\begingroup$ It seems reasonably fast to me; how much lag are you seeing? $\endgroup$
    – Mr.Wizard
    May 28, 2012 at 8:05
  • $\begingroup$ About a second, but If you increase the size of the grid it gets worse fast. $\endgroup$
    – M.R.
    May 28, 2012 at 8:09
  • $\begingroup$ Okay, if I make the grid bigger, e.g. 150x150 I see the lag. What is your application for this many Mouseovers? Perhaps there is a faster approach. $\endgroup$
    – Mr.Wizard
    May 28, 2012 at 8:12
  • $\begingroup$ What platform as you on? Linux? On a fairly outdated Windows machine I can highlight about 6-8 cells per second. $\endgroup$
    – Szabolcs
    May 28, 2012 at 8:21
  • 1
    $\begingroup$ I had similar problems: I wanted the user to be able to click on a grid. Solved the problem by having just one click event and determining the bin from the mouse coordinates manually. $\endgroup$
    – Ajasja
    May 28, 2012 at 13:17

1 Answer 1


I think the problem is not the Mouseover itself, but with the redrawing of the Framed elements.

This, for example, is much faster:

  Mouseover[Style[" ", Background -> Blue], 
            Style[" ", Background -> White]], {i, 50}, {j, 50}], Spacings -> 2,
  Frame -> All]

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