Matrix: JS error in the control panel (rowInfo[index] is undefined)

Question

Weird error in the control panel. I'm using the Matrix field in one channel and as a field in Low Variables.

When i start filling out a new entry things work like a charm. But when i try to open en existing entry i get the following JS error as soon as i open the tab containing the matrix field.

Tijdstempel: 18-01-13 16:27:00
Fout: TypeError: rowInfo[index] is undefined
Bronbestand: http://www.urlhere.nl/themes/third_party/matrix/scripts/matrix.js?2.5.2
Regel: 90

This error 'freezes' the entire matrix field. Basic textfield are still editable but the assets field are frozen. Also removing existing lines becomes impossible but adding new ones is possible. New lines are numbered from 1 as if the others lines don't exists.

Any ideas?

Using ExpressionEngine 2.5.5 and Matrix 2.5.2

With kind regard, Bas van Ginkel

Answer 1

Sometimes the sollution to a problem is a simple one. After uploading the matrix files in the themes directory the problem disappeared.

TAKE HOME MESSAGE
When in doubt reupload the themes file to try and solve the problem.

;)