I downloaded Oxygen & did an install new S/W from the Eclipse menu for the STM32 plugin, downloaded from the site -
I compiled my project (written in C, targeted at an STM32F072) without any issues. A few days later, I came back to the PC with Eclipse installed & the STM32 plugin had vanished, as well as the URL link to the openSTM32 site. Seemed bizarre, but after adding the link again & downloading the plugins all is well again. This has now happened twice on two different PCs. Not difficult to fix, but really weird?