Word PlugIn - Number of rows limited for custom-definitions?

Hello,

we have a field that should only be printed for a small number of customers.

We solved this by using following Expression:

<?if@inlines:H_CUSTOMER_NUMBER='12177' or H_CUSTOMER_NUMBER='157722'  or H_CUSTOMER_NUMBER='19448'  or H_CUSTOMER_NUMBER='17866'?>

This works fine so far, but now we want to add another customer number, which is not possible.

No further typing is accepted, no error-information appears.

Does someone know if number of characters is limited here?

Thanks

Thomas