An arrow is far more than a plain line. Right-click a connector to open its menu, where two categories share the styling controls: Line for the line itself and Pointer for the arrowheads. The settings are independent, so you can mix a thick dashed line with a hollow arrowhead, for example, to match a notation you have in mind.
Line shape and weight
The Line category holds these controls, top to bottom:
- Thickness snaps to four presets: Thin, Medium, Thick and Extra thick.
- Line style picks the geometry: Straight (a single line, the default), Curved (a gentle bezier bow), or Angled (an axis-aligned L-shaped elbow). Curved and angled lines expose a draggable handle so you can shape the path by hand, covered in Curve and Elbow Handles.
- Line pattern sets the stroke to Solid, Dashed, Dotted, Dash-dot, Long dash, or Dash-dot-dot.
- Pass Behind Boxes controls what happens where the line crosses another box (below).
- Start at Exact Anchor appears when the arrow's start is pinned to a shape. Several arrows pinned to the same point fan out side by side so their ends don't pile up; switch this on to keep this arrow's start exactly where you connected it.
Select several arrows and Thickness, Line style and Line pattern apply to all of them at once. Pass Behind Boxes and Start at Exact Anchor are set one arrow at a time.
Passing behind boxes
With boxes packed close together, an arrow drawn straight over the top of one looks like it belongs to the box it crosses. So instead, the line breaks a little before the box and picks up again on the far side, as though passing underneath. A fan of arrows from one parent out to several children stays readable instead of turning into a thicket.
This is on by default for every arrow, and applies to every box in the way, not just the first. Boxes the arrow actually connects are never cut, and neither are section frames (everything inside a frame sits on top of it), shapes with no fill, or plain text, annotations and drawings (there is nothing to hide behind, so a gap would just look broken).
Turn it off for a particular arrow with Pass Behind Boxes in its Line category, for the times drawing over the top is what you want. The arrow stays clickable across the gap either way, so you never have to hunt for a visible piece of it to select.
Line colour
To recolour the arrow, open the Style category in the same menu and expand Colours:
- Line sets the stroke colour, with the usual preset chips and a custom picker.
- Pointer sets the arrowheads' colour separately, so a grey connector can carry a red head. Until you set it, the heads follow the line.
- Reset to Theme underneath snaps the arrow back to the active theme's connector colour.
Arrowheads
The Pointer category controls the heads on each end:
- The first row, "Pick which end(s) of the arrow have a pointer", chooses which ends carry a head: Start only, End only, Both ends, or No pointers.
- Arrowhead size offers Small, Medium, Large, and Extra large, independent of the line's thickness. It sits below the end choice so you pick whether you want a head before sizing it.
- Arrowhead shape picks the head's look: Filled triangle (the default), Hollow triangle, Open (a V with no fill), Dot, Hollow dot, Filled diamond, or Hollow diamond, and the five ER ends: One, Zero or one, Many (a crow's foot), Zero or many, and One or many. These pair well with formal notations: a hollow triangle reads as UML inheritance, a diamond as aggregation or composition, and the ER ends as a table's cardinality where a relationship meets it. An arrow can carry a different ER end at its start, so one line says "one customer places many orders"; an imported ER diagram sets both for you.
With No pointers chosen, the size and shape rows hide, since there is no head to style.
Labels
Double-click an arrow's line to add a label (a fast double-click always opens the label, even on an arrow that wasn't selected). The label sits on the line at its midpoint, with the line broken open around it (a label too long for a short arrow sits beside the line instead), and you can drag it along the line and to either side to reposition it. Once an arrow has a label, its context menu gains a Caption category: bold, italic, underline, strikethrough, size, a Text colour and a Background colour for a plate behind the words.
The label colour defaults to the arrow's stroke colour, so it matches the line automatically until you choose otherwise.
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