Improve the search box

Now if we click the search box, the whole text will be erased.
This is annoying sometimes, I often add something or change a part of my keywords from previous text, so could you do a litte change to it?

When the cursor moved onto the search box, all the text will be checked.
This is the most convinient way IMO, and won't distrub the users who get used to the way currently using.