Issue started recently after last patch. Will be unable to type after typing in a sign that is placed on an object or on the ground.

Steps to recreate/found issue. 

1. Place Sign
2. Type in sign
3. Escape out of sign

Results:

1. Cannot type in game chat, window will launch but will not take input.
2. Enter Key stops working and ESC key will not exit window, Controller (xbox) "B" button will exit sign or chat window. 
3. Cannot type in new sign or chat window. 
4. Can go back to original sign and type again.

Troubleshooting:

1. Left realm and came back to realm - No change, still cannot type in chat or new signs. 
2. Restart client - can type again, but if placing sign and typing into the sign and exiting the issue starts again.
3. Checked external of application after issue starts - Typed in Microsoft Word or Notepad, system takes full input. 
4. Re-install Minecraft client (default everything) - Can recreate issue from steps above. 
5. Created a new easy mode world (not on realms) - Recreated issue above using same steps.  
6. Placed three signs in new world and typed, but deleted text and exited sign. Still had the ability to type in chat and on other signs. Did this two times and then on the third attempt left the text. Lost the ability to type again in chat or on signs. Can still edit the sign with the text. 
7. Continued testing in newly created world - Found that sometimes the issue does not start until the second sign placed and typed in. 
8. Found that if you delete the text that was typed and exit the sign, can type again in chat and on other sign. If removing the sign before removing the text will be unable to type even if placing same sign. 
9. Found that if unable to type in realms that the issue persists if exiting realms and launching private world within the same launched application session. This is also true when moving from private world to realms. 

Additional factors: 

1. This occurs before and after latest windows updates and restarts.
2. Have used birch and oak to recreate issue, did not test other materials. 
3. Not seeing the issue with other users on the realm, yet. 
4. Used both floor/wall signs as well as hanging signs.