I had the same thing happen to me not with a spinner but with a text control. What was causing it for me was the refresh in the InteractiveChange Event.

Charles

>I found a interesting bug in VFP, which can be solved by the apparently redundant sentence THIS.VALUE=THIS.VALUE. To show the bug:
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>CREATE a table with a numeric field and a text field.
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>APPEND a record to it
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>Create a blank form, and include the table in its environment.
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>Add a spinner to the form; set its ControlSource to the numeric field, and in its INTERACTIVECHANGE code write THISFORM.REFRESH().
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>Add a textbox to the form; set its ControlSource to the text field, and in its REFRESH code write THIS.VALUE = STR(THISFORM.SPINNER.VALUE).
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>Run it, and try to change the spinner by clicking on its arrow buttons!! What I get is: the spinner changes for an instant, and goes back to its original value. (This doesn´t happen if the objects have no ControlSource.)
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>The solution? Add THIS.VALUE=THIS.VALUE at the beginning of the SPINNER.INTERACTIVECHANGE code.
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>Weird!!