Why does text always jump around and off the page, etc.

When trying to add staff text, it quite often (or usually) gors crazy if I try to move it a little higher -- by crazy, I mean it joumps to another page or something - becomes just lost. But just continuing to drag it back down will often result of a brief image of the text that suddenly jumps off the bottom of the page.

It seems that bringing some more "smarts" to placement of objects is counter-productive.