I've somehow managed to make my TortoiseGit commit dialog commit message text box to be one line long. <img src="https://i.stack.imgur.com/h2HG8.png" alt="enter image description here"> However I cannot find a setting that would reset it. I've have uninstalled and removed TortoiseGit and installed the latest versions. But it's still returns. Oh and resizing the dialog doesn't fix it.

Move mouse to the position between Message and Changes made (double-click on file for diff) group box (see following figure) <img src="https://i.stack.imgur.com/TjNie.png" alt="enter image description here"> Then drag down to the position where you want. And it's bigger: <img src="https://i.stack.imgur.com/L6NRX.png" alt="enter image description here">