Development tools for Zephyr on STM32Workbench for Zephyr: VS Code extension to set up, build, flash and debug Zephyr applications on STM32.Devicetree manager: browse, edit and visualize Zephyr devicetree, STM32CubeMX-like for Zephyr.
Didn't find an actual cause. Uninstalled SW4STM32 in Eclipse plugins installer and removed all fr.ac6* folders and files + artifacts.xml in Eclipse folder . Then installed again and problem gone.