[Plugin: Advanced Search Widget] Search box > OK but in Dutch it is Zoek en does'nt fit in

Plugin Advanced Search Widget.

I dont mind to place OK in the area.
But my dutch wordpress put automaticly the dutch word “Zoek” in the little grey area but does not fit good.

Does some one know how to chache the text in the little grey area?

Thanks,
Sam

https://www.ads-software.com/extend/plugins/advanced-search-widget/