Improved `chars` String for the `random_str` method: "T" was present 2 times, but the "Y" was missing. The "j" was also missing.
Merge pull request #2597 from herom/master

Improvement: Enhance the 'chars' String of the 'random_str' method in foundation.js
Fixed mobile topbar

- The top bar menu was not showing all child elements from the second level and up in the mobile state.
- Fixed a height issue.