I use Toad often with VPN. If I leave Toad for a while, long enough for the Oracle connection to go "stale", and then do an operation (a select or whatever), Toad crashes. I looks like the window handling is out of order or something:
There are also several "Out of system resources" alert boxes. I then have to kill the Toad process.
One precaution could be "reconnect", but it's cumbersome to do that all time. Sometimes the "Reconnect" box option appears, but not always.
Toad version: Toad for Oracle 32bit 12.1
Windows 7 64 bit
Oracle 22.214.171.124.0 32 bit client