As another user asked about firefox:
Increase limit of bookmark folders in Firefox?
I would like to increase the number of folders that you are presented with when you press the add bookmark star in Chrome. As it is now, you get a choice from the last five used folders, "bookmark bar", "other bookmarks" or choose another folder. The last five folders are listed in a last in last out progression, so if you happen to bookmark five different pages to five different folders the sixth folder chosen would move the first one out.
It would also be a nice option if along with increasing the number of presented folders, to pin chosen folders to always appear in the pulldown selection, regardless if I have used it recently or not, so if I find that I have bookmarked 10 different pages to their respective folders, that "my" most used folders are always quickly available.
A different solution would be to allow the creation of a(nother) special folder called "pinned favorites" that would be displayed along with "bookmarks bar" and "other bookmarks" that contain the folder selection that you choose to not be a part of the sequential deletion of the five "most recently used" folders. This folder would display the pinned folder selection once "pinned folders" was selected as a pulldown similar to the choose another folder option.
Best Answer
Unfortunately, this is a"no" answer, per the comment to the question: this is not possible to modify.
Your best bet is to create a bug, or submit your own patch.