New computer. Downloaded Thunderbird and added 3 gmail accounts. Worked well for about a week and then started receiving strange screen when clicking the "write" control. Screen has no option to send the email. Has a gray frame around it. Can type in info - to, subject, and text but no way to send it. If you close it, asks if want to save to draft. (see image attached) I saved to "draft" but same screen with no send comes up when I pull up draft message. Have checked all settings for outgoing stmp and all are as directed (and same as old computer). Help please.