[REVIEW 3-5] fix various overlapped controls in the Options dialog

Hi,

There are some small UI fixes in 
1535eed3d40d9741f3cdf68d32bc132e2a39f287 on master:

1. https://bugs.freedesktop.org/attachment.cgi?id=55691 - 'Enable 
experimental (unstable) features' field covered/cropped by grey
fragment:
Tools menu > Options item > LODev section > General.

2. https://bugs.freedesktop.org/attachment.cgi?id=55693 - Transparency 
scale field (75%) covered by grey fragment.
Tools menu > Options item > LODev section > View

3. https://bugs.freedesktop.org/attachment.cgi?id=55694 - 'N' Minutes 
field covered by grey fragment,
Tools menu > Options item > Load/Save section > General

The attached screenshots show how it looks now.

Regards,
Ivan

Attachment: experimental-features.png
Description: PNG image

Attachment: save-autorecovery-information-every-n-minutes.png
Description: PNG image

Attachment: transparency.png
Description: PNG image