The "Continue" button from Distribution Wizard is not properly displayed

Steps to reproduce:

1. Click on Add
2. Click on Wiki
3. Create a new wiki
3.1. Fill the fields from Step 1
3.2. Click on the "Go to next step" button
3.3. Choose the "User Scope" and "Membership Type" from Step 2
3.4. Click on the "Create" button
4. Distribution Wizard
4.1. Click on "Continue" button
4.2. Click on the "Install" button from User Interface

Then, when you want to press on the "Continue" button you will see that the button is not properly displayed (see the attachment).