>Why the timer disable the methods in a grid ??

I guess it's not the timer, but some piece of code which has closed the grid's alias and reopened it. When that happens, the grid rebuilds - and you get a blank grid, custom objects, code etc all gone, it's a default grid.

To prevent that, start with http://fox.wikis.com/wc.dll?Wiki~GridSafeSelect~VFP