Hold Shift When Drawing Rectangles in Paint.NET

Holding down the Shift key while drawing a rectangle in Paint.NET constrains the shape to a 1:1 aspect ratio, transforming the rectangle into a perfect square. This keyboard shortcut works across both the vector-based shape tools and the selection tools, allowing users to create uniform geometric elements quickly without needing to calculate pixel dimensions manually.

The Shapes Tool (Drawing a Square)

When using the Shapes tool with the shape type set to Rectangle:

1. Click and drag on the canvas to begin creating the shape.
2. Press and hold the Shift key at any point while dragging.
3. The rectangle will instantly snap into a symmetrical, four-sided square.
4. Release the mouse button first to finalize the dimensions, then release the Shift key.

If you release the Shift key before releasing the mouse button, the shape will revert back to a freeform rectangle.

The Rectangle Select Tool (Square Selections)

The modifier function works identically when making selections:

1. Choose the Rectangle Select tool from the Tools panel.
2. Click and drag over the region of the image you want to highlight.
3. Hold the Shift key to lock the selection boundaries into an exact square.
4. Release the mouse button to set the selection area.

Additional Behaviors

• Mid-Draw Toggle: You can press and release the Shift key repeatedly while dragging the mouse to toggle back and forth between a freeform rectangle and a locked square.
• Consistency Across Tools: This constraint behavior is standard across Paint.NET. Using the Shift key while drawing an ellipse will constrain it to a perfect circle, and holding it while drawing a line will constrain the line's angle to 15-degree increments.