This wallet is the worst I've ever used. It's always lagging, bugging out, etc.
I have over 2500 coins and I try to send them to itself and it says not enough coins. Nonstop issues since the most recent update.
We have run GUI wallets in three platforms (ubuntu, windows and mac) without any issue. You might feel lag while syncing, but it is good after synced. May I know what is the OS and spec of your machine? It could be your machine low hardware spec issue.