The marquee tools decide which pixels you are working on; the Move and Transform tools decide where things go. They share one gesture engine, so dragging pixels behaves the same whichever of them you started from.
| Rectangular Marquee M | Drag a rectangle. |
| Elliptical Marquee M (cycle) | Drag an ellipse. |
| Lasso / Polygonal Lasso L | Draw freehand, or click corner by corner. Close the shape near its start point. |
| Magic Wand W | Click to select an area of similar color. |
While you are dragging a rectangle or ellipse:
| Shift (after the drag starts) | Constrain to a square or circle. |
| Alt (after the drag starts) | Draw outward from the center instead of from the corner. |
| Esc | Cancel the selection you are drawing. |
The tool options bar has four combine modes — New, Add, Subtract and Intersect — and each has a keyboard equivalent you can hold before starting the drag:
| New selection (default) | Replaces whatever was selected. |
| Add — hold Shift | Union with the existing selection. |
| Subtract — hold Alt | Cuts the new shape out of the existing selection. |
| Intersect — hold Shift+Alt | Keeps only the overlap. |
Antialias (options bar) gives the selection edge soft, partially-selected pixels instead of a hard on/off edge. It is on by default for the ellipse and lasso, off for the rectangle.
Tolerance is how different a color may be and still be selected — raise it to grab more. Contiguous limits the selection to the region you clicked; turn it off to select every matching pixel in the layer. Sample all layers tests the composited image rather than just the active layer.
This is the distinction worth learning. With a marquee tool active and the mouse inside a selection, what you drag depends on whether you hold Ctrl:
| Drag (no modifier) | Moves the selection outline only. The marching ants slide; the image underneath does not change. Useful for repositioning a selection you drew slightly off. |
| Ctrl+drag | Moves the pixels. The selected pixels are lifted out of the layer, leaving a hole behind, and float above it while you drag. Recorded in History as Move Selection. |
| Ctrl+Alt+drag | Moves a copy of the pixels. The original stays where it was. Recorded as Copy Selection. |
The cursor tells you which one you will get before you press the button: the move cursor for the outline, the cutout cursor once Ctrl is down.
Floating pixels stay floating — you can keep nudging them — until you click outside the selection, choose another tool that needs them, or deselect. At that point they are stamped back down into the layer. One drag is one History step, so a single Undo puts everything back.
Right-click inside a selection (or use the Select menu) for Deselect, Invert, Feather…, Layer via Copy / Layer via Cut (which promote the selected pixels to a new layer instead of floating them), Define Brush…, Define Pattern…, Transform Selection, Quick Mask, and Load / Save Selection.
V selects the Move tool. Drag a layer to move it. Drag on empty canvas to rubber-band a group of layers into the selection. Drag a layer onto another document's tab to move it into that document.
If a selection is live, the Move tool acts on the selected pixels: dragging inside the selection floats them, exactly as Ctrl+drag does from a marquee tool (and Alt again makes it a copy).
| Auto-Select | Clicking picks the topmost layer under the cursor. Turn it off to keep the layer you chose in the Layers panel, no matter where you click. |
| Show Transform Controls | Draws a bounding box with handles around what is selected. This is what makes handles grabbable — see below. |
| Object / World | Whether the box follows the object's own rotation (Object) or stays axis-aligned to the canvas (World). |
| Pivot point | Show a movable pivot and rotate/scale around it instead of the box center. |
With Show Transform Controls on, the Move (or Transform) tool draws a box with eight handles around the target:
Perspective distort is a true projective mapping, not a stretch: drag two corners of one edge inward and you get the receding-into-the-distance look, with the interior of the image foreshortened to match. It works on a layer's transform and on floating selection pixels alike.
When a selection is live, the box belongs to the selection: grabbing one of its handles floats the selected pixels and scales or rotates them, rather than transforming the whole layer. With no selection, the box belongs to the layer and the transform applies to all of it.
With the Move tool, drag out of a ruler to create a guide, and drag an existing guide to reposition it (drag it off the canvas to delete it). Guide moves are undoable. Selections and layers snap to guides while you drag.