Source : http://www.macosxhints.com
Thanks to VRic for the info.
Many users have noticed that selecting text, then dragging the selection somewhere, which was obvious on Mac OS9, is not always available on OSX. As a result they tend to not expect it rather than be disappointed and irritated. Some applications (like iCab) function normally and others (like Safari) don't work most of the time -- but not always. The first click for dragging and dropping deselects the text, forcing you to start over. Eventually, after the 3rd time, you give up and do a copy and paste instead.
The problem is actually with the preferences of Cocoa applications: the delay before a selection of text becomes draggable.
This is a stupid preference, in my opinion. A selection changing behavior suddenly without indicating any difference to the user (separate from the exasperating failure if you try) is bad enough, but not every selection is affected, only a text selection. The inconsistency is bad. Additionally only Cocoa applications experience this. As if that were not bad enough, each application can have its own preference. This is probably a record for inconsistency in OS X.
To modify this, type the following in the Terminal and then restart all Cocoa applications so they register the changes:
defaults write -g NSDragAndDropTextDelay -int 100
The 100 value is for 100 millisecondes (1/10th of a second, instead of the 1 second default)
-g stands for "global" (every Cocoa application)
You can put whatever value for the time you want in milliseconds, or you can put a negative value to deactivate the drag and drop of text in every Cocoa application (which is a funny idea).
