Parameter choices of type string are not displayed correctly in an experiment design

I have an algorithm, which takes as parameter a string, which can be selected from a list. The list is correctly displayed in the algorithm page, but when I try to design and run an experiment, each letter is displayed individually, including the [, ] and , characters. As a consequence, I cannot run the experiment, but I rather get the error message:

"Traceback (most recent call last):\n  File \"/remote/sw/beat.web/src/beat.web/beat/web/experiments/models.py\", line 131, in create_experiment\n    experiment.save()\n  File \"/remote/sw/beat.web/src/beat.web/beat/web/experiments/models.py\", line 291, in save\n    raise SyntaxError(message % '\\n  * '.join(errors))\nSyntaxError: The experiment isn't valid, due to the following errors:\n  * /globals/siebenkopf/GaborGraphSimilarity/10/gabor_jet_similarity: cannot convert value `[' to required type: value for `gabor_jet_similarity' ('[') must be one of `['ScalarProduct', 'Canberra', 'Disparity', 'PhaseDiff', 'PhaseDiffPlusCanberra']'\n"

Enjoy debugging! Manuel