An SSD1306 has 8 pins along a 240px header. Horizontal labels need ~36px
each = 288px, so they overflowed the art box and rendered outside the dialog,
over the header and the canvas. Top/bottom labels are now vertical text - what
printed pinout diagrams do - which needs only the side spacing, and the gutter
grows to fit. The preview also clips, so nothing can escape again.