Shape Contextual Tab
Shape tab serves as a contextual tab that defines the appearance of Ellipse, Rectangle, and Line objects.
The following groups of settings are available on the Shape tab:

Outline Style button options are:
None: makes the object line invisible.
Solid: makes the object line solid.
Dot: makes the object line dotted.
Dash: makes the object line dashed.
Clear: makes parts of other objects underneath the line invisible.
Outline Color defines the color of the shape's line.
Thickness defines the object line's width.
Corner radius makes the rectangle corners round. Higher values make the curve broader.

Fill Style options are:
None: makes the object completely transparent.
Clear: makes other objects beneath the active one invisible.
Solid: fills the object with solid color.
Right Diagonal: fills the object with diagonal lines that ascend toward the right side.
Left Diagonal: fills the object with diagonal lines that ascend toward the left side.
Vertical: fills the object with vertical lines.
Horizontal: fills the object with horizontal lines.
Cross: fills the object with crossed lines.
Cross Diagonal: fills the object with diagonally crossed lines.
25% of color: sets fill color opacity to 25 %.
50% of color: sets fill color opacity to 50 %
75% of color: sets fill color opacity to 75 %.
Background Color defines the color of the shape's fill.

Group objects: adds selected objects to a group.
Group objects: unites the selected objects and makes them behave as a single object.
Ungroup objects separates previously grouped objects.
Arrange: defines how objects are positioned in a group.
Bring forward: moves the selected object up one layer.
Bring to front: moves the selected object to the top of the object stack.
Send backward: moves the selected object down one layer.
Send to back: moves the selected object to the bottom of the object stack.
Align group allows setting the alignment and spacing for objects on the design surface. All objects can be aligned according to the neighboring object or according to the document border.
Horizontal alignment options are:
Left: aligns the selected objects with the left edge of the leftmost object or with the left edge of the first selected object. If a single object is selected, it is placed on the label's left border.
Center Horizontally: aligns the selected objects with the horizontal center of the largest selected object or with the horizontal center of the first selected object. If a single object is selected, it is placed in the horizontal center of a label.
Right: aligns the selected objects with the right edge of the rightmost object or with the right edge of the first selected object. If a single object is selected, it is placed on the label's right border.
Distribute Horizontally: equalizes horizontal spacing between the objects.
Vertical alignment options are:
Top: aligns the selected objects with the top edge of the topmost object or with the top edge of the first selected object. If a single object is selected, it is placed on the label's top border.
Center Vertically: aligns the selected objects with the vertical center of the largest selected object or with the vertical center of the first selected object. If a single object is selected, it is placed in the vertical center of a label.
Bottom: aligns the selected objects with the bottom edge of the lowest object or with the bottom edge of the first selected object. If a single object is selected, it is placed on the label's bottom border.
Distribute Vertically: equalizes vertical spacing between the objects.
Tip
Align to label/form is achieved by holding the <Ctrl>
key and clicking the above listed align icons.