For one contact I have only a title bar

[aberz]

I have several contacts with whom I converse regularly. For one, I clicked something unintended. For him, I have only the title bar on my screen. If I open any other, I get a regular window with menu, icons, from, and an input box. I don't know what I did to "Tom" and I don't know how to fix it. Can someone help me, please. Thanks!

[Shmanky]

double-click on the bar

[aberz]

Thanks!! I had tried clicking the maximize icon, which merely made the title bar fulll-screen wide. I guess it didn't occur to me to double-click it.