When editing a document in gedit, saving it somewhere, then choosing "File" -> "Save as..." to save a copy somewhere else, then, as soon as the "Save as..." dialog appears, the name of the file is editable and selected. This is good as it means that one can delete it very quicly (eg. backspace) and enter something new, or, one can get rid of the selection (eg. left arrow) and edit the name.
IF one chooses to navigate to another directory (with the intend to save the copy of the document there), clicking the name text field to edit the file name will immediately remove the selection. Having all of the text selected was a nice property. Now, if I want to delete the text to enter a new name, I have to click and hold the backspace button until all the letters have been deleted. Inconvenient.

Suggestion:
When the text field has been out of focus and is then refocussed upon, don't remove any selection that may be present in the text field. A second invocation of focus (eg. by another mouse click), can then have the function of removing any selection.