How to turn off Compiz's "drag to maximize" behaviour?

You can disable it from ccsm : Click to install

Go to Windows management--> Grid --> Edges --> Re-size Actions

Top Edge: change it to none.

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Recommended

If you simply want to turn off this feature then run the following in a terminal:

gconftool-2 --set /apps/compiz-1/plugins/grid/screen0/options/top_edge_action --type int 0

Alternatively - with a GUI, use gconf-editor:

Compiz configuration options

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