Issue Summary

When @ mentioning a member, pressing the tab key quickly will result in @ mentioning the member editing the card 

Steps to Reproduce

1. Open the card back 
2. @ mention a member on the board by typing their name
3. Select tab to choose the member immediately after typing the first 3 letters of the member's name

Expected Results

A member with a name that matches the letters typed in Step 3 will be mentioned.

Actual Results

The member editing the card is mentioned.

Workaround

Pause before pressing tab to allow for the correct member to be selected.