Hi,
You'll need to manipulate the style of the fieldset and input div tags. This example is just a starting point. It impacts the display of the dashboard when editing and may break accessibility:
<form version="1.1" theme="dark">
<label>Multiselect Width</label>
<fieldset submitButton="false">
<html>
<style>
.fieldset {
display: table;
}
#fixed_width_multiselect {
display: table-cell !important;
width: 500px !important;
}
#fixed_width_multiselect div[role="listbox"] {
display: table-cell !important;
width: 480px !important;
}
#dynamic_multiselect {
display: table-cell !important;
white-space: nowrap !important;
}
#dynamic_multiselect div[role="listbox"] {
display: table-cell !important;
}
</style>
</html>
<input id="fixed_width_multiselect" type="multiselect" token="fixed_width_multiselect_tok">
<label>Fixed-Width Multiselect</label>
</input>
<input id="dynamic_multiselect" type="multiselect" token="dynamic_multiselect_tok">
<label>Dynamic Multiselect</label>
</input>
</fieldset>
</form>
Note that your Splunk administrator may disable the <html> tag in dashboards, in which case you'll need their assistance adding a CSS file to the app and referencing it with the stylesheet attribute of the <form> tag.
