You are right, not only the log window, all windowframes have a strange behaviour when resizing.
To see it, when starting with a nice small window, what happens if you maximize and then reduce:
1. if you adjust width of log window maximized, then switch to reduce, window width is to big, and you have to move the separator befor you can shrink horizontally.
2. If you increment on maximized window the height of the lower traffic area, reducing will even in someway flip the contents of the windows.
But i am sure rejetto knows this all, but this things don't affect the basic working of hfs. So as hfs goes on growing with new features, there will be lot of work redesigning menus and windows, and i think we should live with this minor details to allow that the features to serve files and create templates better could be attacked before.
If you need to look at logs fecuently, you can write your logs to disk, even splitting files depending of user, date and so on. Then you can look at them with any editor.