Can’t set height: 0; to fieldset if legend is available


I have a form with collapsible fieldsets. In this example, each checkbox opens a fieldset with help of Bootstrap-Collapse.

The Odd

The fieldset with legend don’t (un)collapse smoothly. The fieldset without legend is fine.

The Known

Bootstrap animates the collapse-elements with overflow: hidden; height: 0;.

Apparently the browsers don’t like to set the fieldset height to actually 0 (zero), if a legend exists.

So the animations runs till only the legend is visible and then show/hide the fieldset.

Can't set height: 0; to fieldset if legend is available

EDIT: Solution

Rip the legend out of the fieldset with float. Solution within the codepen. Thanks @beni-sinca


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Method 1

This is an old topic. <legend> elements were always very vague and there were very many browser inconsistencies around <legend>.

I funny enough had a similar task once and managed to fix it by floating the legend element and making sure it has the right width.

In your case I think something like this would do the job:

legend.col-form-label {
    float: left;
    width: 100%;
    max-width: 100%;
    flex: 0 0 100%;

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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