Increase width of select values in issues page
The following is issues page in minimalflat2 theme.  All texts of `select` type values are not displayed.

![minimalflat2](https://user-images.githubusercontent.com/238681/32403900-6f79e42c-c188-11e7-8f7f-a317ab4f12a4.png)

The following is the same page in Default theme. The layout is not so good, but all texts are displayed. It seems Default theme does not specify `max-width`.

![defaulttheme](https://user-images.githubusercontent.com/238681/32403899-6eaf3fc4-c188-11e7-9d62-76b949891da8.png)

Can you consider to increase `max-width` of `fieldset#filters td.values select` ? Or is there any other better option?