"create" filter button disabled

- windows 10
- `FF 58.0b11 (64-bit) uBo 1.14.21rc4`
or
- `chrome Version 64.0.3282.24 (Official Build) beta (64-bit) uBo dev build 1.14.21.104`

- go to `google.com`
- open dashboard, logger
- refresh page
- choose some element to block for example:
`notifications.google.com`
- `Click on the 4th cell of a log entry` => to create a static filter
- create the filter => `||notifications.google.com`

Now refresh the page, go into "my filters" tab, delete the filter.
Repeat exactly the same steps above.
When the filter was created exactly as in the first step => **the "Create" button is disabled**.

It does not matter which is the test page.