The way that we set the width of the `dropdownToolbarButton`-select is very old, and despite some improvements over the years this is still somewhat hacky.
In particular, note how we're assigning the select-element a larger width than its containing `dropdownToolbarButton`-element. This was done to prevent displaying *two* separate icons, i.e. the native and the PDF.js one, since it's the only way to handle this in older browsers (particularly Internet Explorer).
Given the currently supported browsers, there's however a better solution available: use `appearance: none;` to disable native styling of the select-element. [According to MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/appearance#browser_compatibility), this is supported in all reasonably modern browsers.
This way we're able to simplify both the CSS rules and the JS-code that's used to adjust the `dropdownToolbarButton` width in a localization aware way.
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