Menu button changes size when opening an application

[akanashiro]

I have been experiencing a minor bug in menu button in Cinnamon.
When I open an application, menu button slightly resizes its width.

Setup:
- cinnamon 1.6.7
- Spanish Language installation.
- menu button with icon.
- default shortcut buttons (show desktop, firefox, terminal).
- default cinnamon theme
- default gtk-theme and default icon-theme (Mint-X).
- full rgb antialas

Steps to reproduce:
- open an application
- menu button resizes X pixels.

Tries:
- At first I thought it was a theme problem, but I tried several themes and it repeated the same behaviour.
- I changed menu button position and it repeated the same behaviour.
- If I disable the menu icon, this problem doesn't happen.

Screenshots:

Before opening an application:


After opening an application:


Did any one experience this issue?

[steppres]

Yes, I have the same problem. Tried resetting panel, creating new user profile bit nothing seems to work.

[akanashiro]

Same problem in Cinnamon 1.8.x