Using Find in Text Wrangler (Mac) requires 2 extra steps to work sometimes - why?

When I've got a css or php file opened with Text Wrangler and I do a 'find' for a term that I know is on the page, I oftentimes have to click my mouse and move the scroller thing (located on the right) and click inside the Text Wrangler file that's opened, usually some blank space up top, in order for the finder to do its job.

'Not found' is what happens if I don't do this.

Click the scroll button to reposition the cursor any place random on the page, and then I'll be able to locate what I was looking for.

I don't have grep box ticked.

It's just a plain old search for a term.

When I search for a term while using Text Edit, I never have to do this.

Why?

I am using Mac OS 10.6.8