as best as I can surmise what happened here:

• I was on the "subversion commits" tab of a project
• I went to an issue in a different project that didn't have that tab
• none of the tabs in that aread was selected, so I just had the empty box.

It looked like there was no comments however - confusing. I had to click the comments field to get them back.

If the version control tab is not there, it should select the default tab.