>I put a listbox and a grid (based on cursor),
>the contents of grid change when listbox value changed, if I'm not add "Thisform.mygrid.refresh()" on the end of listbox.interactivechange code, the contents of grid didn't change, but if I put refresh, contents of grid changes and also grid position changed, the grid looks also messy, why this happens ?
>I tried set lockscreen=.t. and lockscreen=.f.(after refresh) but still got a same result.
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>TIA :)

If during this process you overwrite grid.recordsource then you force grid to be rebuilt from scratch with defaults on column.controlsource, width (is this what you call 'messy'?) etc. So the remedy is either keep/restore all settings or don't overwrite the recordsource.