Default values for numbers in custom widgets do not work

[sidamos]

I have a custom widget with a setting of type Number. When I configure some number as default value, I get a runtime error when Habpanel renders a new widget of this type:

vendor.js:119 Error: [ngModel:numfmt] http://errors.angularjs.org/1.5.11/ngModel/numfmt?p0=14
at vendor.js:6
at Array. (vendor.js:183)
at vendor.js:293
at m.$digest (vendor.js:144)
at m.$apply (vendor.js:147)
at HTMLAnchorElement. (vendor.js:281)
at eg (vendor.js:37)
at HTMLAnchorElement.d (vendor.js:37)

This is how I use the config value (labelFontSize):
<span ng-style="{'font-size': (config.labelFontSize) + 'pt'}">{{config.name}}</span>
Workaround: Use type of String.