I do not understand why this works only once!
Calling form2 from form1 in the same way, filling the searchfield with the same value .... and the grid is reset to default textboxes ?????

How are you populating the grid's RecordSource? Are you using the trick of setting it to an empty string and the filling the cursor using an SQL SELECT? If so, try using what I call a "Safe Select" instead. Put the results of your query into a temporary cursor, ZAP the grid's RecordSOurce, and APPEND the results FROM the remporary cursor into the grid's RecordSource. ZAPping the cursor does not close it.