I've dream about this feature for a long time and finally implemented!

• Send button deactivation on key/value size limits reached
• Counter for key / values on keyup
• Colorized highlight (greed / red) or hidden on empty

https://github.com/kevacoin-project/kevacoin/pull/39

to not wait for new release:
https://github.com/kvazar-network/kevacoin/tree/kvazar