…be seen when selecting the next operator #3221
### What problem does this PR solve?
Fix: Fixed the issue that the content of the Dropdown section cannot be
seen when selecting the next operator #3221
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Feat: The delete button is displayed only when the cursor is hovered
over the connection line #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Feat: Modify the style of the canvas operator node #3221
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
