Put the summary of the bug you're having here

What I expected to happen was...:
dialog for opening a page

What actually happened was...:
just a crash (look in crash report)

Steps to Reproduce:
1. put tellraw @a {"text":"","extra":[{"text":"To Get To My Youtube Click Here!","color":"dark_red","bold":"true","underlined":"true","clickEvent":{"action":"open_url","value":"www.youtube.com/bltboom1"}}]} in a command block
2. click the button on the command block
3. click on the link