Indicate that there was a problem with the values in a statement when trying to validate

[Torjas]

When clicking on validate the document is first checked if the values in the statements are all known. If not, a message will appear below that statement.
However, when there are too much statements to fit all on the screen and on of the statements not shown on the screen has an error clicking on the validate button seems to do nothing. Only after scrolling down the error is visible.