WordPress · aaronrobertshaw · Mar 28, 2022 · Mar 25, 2022 · Mar 25, 2022 · Mar 28, 2022
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Enhancements
+
+- Update `BorderControl` and `BorderBoxControl` to allow the passing of custom class names to popovers ([#39753](https://github.com/WordPress/gutenberg/pull/39753)).
+
 ### Internal
 
 -   `BaseControl`: Convert to TypeScript ([#39468](https://github.com/WordPress/gutenberg/pull/39468)).

@@ -25,6 +25,7 @@ const BorderBoxControlSplitControls = (
 		enableAlpha,
 		enableStyle,
 		onChange,
+		popoverClassNames,
 		value,
 		__experimentalHasMultipleOrigins,
 		__experimentalIsRenderedInSidebar,
@@ -49,20 +50,23 @@ const BorderBoxControlSplitControls = (
 				hideLabelFromVision={ true }
 				label={ __( 'Top border' ) }
 				onChange={ ( newBorder ) => onChange( newBorder, 'top' ) }
+				popoverContentClassName={ popoverClassNames?.top }
 				value={ value?.top }
 				{ ...sharedBorderControlProps }
 			/>
 			<BorderControl
 				hideLabelFromVision={ true }
 				label={ __( 'Left border' ) }
 				onChange={ ( newBorder ) => onChange( newBorder, 'left' ) }
+				popoverContentClassName={ popoverClassNames?.left }
 				value={ value?.left }
 				{ ...sharedBorderControlProps }
 			/>
 			<BorderControl
 				hideLabelFromVision={ true }
 				label={ __( 'Right border' ) }
 				onChange={ ( newBorder ) => onChange( newBorder, 'right' ) }
+				popoverContentClassName={ popoverClassNames?.right }
 				value={ value?.right }
 				{ ...sharedBorderControlProps }
 			/>
@@ -71,6 +75,7 @@ const BorderBoxControlSplitControls = (
 				hideLabelFromVision={ true }
 				label={ __( 'Bottom border' ) }
 				onChange={ ( newBorder ) => onChange( newBorder, 'bottom' ) }
+				popoverContentClassName={ popoverClassNames?.bottom }
 				value={ value?.bottom }
 				{ ...sharedBorderControlProps }
 			/>

@@ -116,6 +116,26 @@ _Note: The will be `undefined` if a user clears all borders._
 
 - Required: Yes
 
+### `popoverClassNames`: `Object`
+
+An object defining CSS classnames for all the inner `BorderControl` popover
+content.
+
+Example:
+```js
+{
+	linked: 'linked-border-popover-content',
+	top: 'top-border-popover-content',
+	right: 'right-border-popover-content',
+	bottom: 'bottom-border-popover-content',
+	left: 'left-border-popover-content',
+}
+```
+
+By default, popovers are displayed relative to the button that initiated the popover. By supplying classnames for each individual popover, it is possible to add styling rules to align the popover positions to an unrelated design element, for example, the sidebar inspector in the block editor.
+
+- Required: No
+
 ### `value`: `Object`
 
 An object representing the current border configuration.

@@ -51,6 +51,7 @@ const BorderBoxControl = (
 		linkedValue,
 		onLinkedChange,
 		onSplitChange,
+		popoverClassNames,
 		splitValue,
 		toggleLinked,
 		__experimentalHasMultipleOrigins,
@@ -76,6 +77,7 @@ const BorderBoxControl = (
 						placeholder={
 							hasMixedBorders ? __( 'Mixed' ) : undefined
 						}
+						popoverContentClassName={ popoverClassNames?.linked }
 						shouldSanitizeBorder={ false } // This component will handle that.
 						value={ linkedValue }
 						withSlider={ true }
@@ -94,6 +96,7 @@ const BorderBoxControl = (
 						enableAlpha={ enableAlpha }
 						enableStyle={ enableStyle }
 						onChange={ onSplitChange }
+						popoverClassNames={ popoverClassNames }
 						value={ splitValue }
 						__experimentalHasMultipleOrigins={
 							__experimentalHasMultipleOrigins

@@ -14,6 +14,14 @@ export type AnyBorder = Border | Borders | undefined;
 export type BorderProp = keyof Border;
 export type BorderSide = keyof Borders;
 
+export type PopoverClassNames = {
+	linked?: string;
+	top?: string;
+	right?: string;
+	bottom?: string;
+	left?: string;
+};
+
 export type BorderBoxControlProps = ColorProps &
 	LabelProps & {
 		/**
@@ -26,6 +34,11 @@ export type BorderBoxControlProps = ColorProps &
 		 * individual side borders, or `undefined`.
 		 */
 		onChange: ( value: AnyBorder ) => void;
+		/**
+		 * An object defining CSS classnames for all the inner `BorderControl`
+		 * popover content.
+		 */
+		popoverClassNames?: PopoverClassNames;
 		/**
 		 * An object representing the current border configuration.
 		 *
@@ -71,6 +84,11 @@ export type SplitControlsProps = ColorProps & {
 	 * changed.
 	 */
 	onChange: ( value: Border | undefined, side: BorderSide ) => void;
+	/**
+	 * An object defining CSS classnames for the split side `BorderControl`s'
+	 * popover content.
+	 */
+	popoverClassNames?: PopoverClassNames;
 	/**
 	 * An object representing the current border configuration. It contains
 	 * properties for each side, with each side an object reflecting the border

@@ -20,6 +20,7 @@ export function useBorderControlDropdown(
 		border,
 		className,
 		colors,
+		contentClassName,
 		onChange,
 		previousStyleSelection,
 		...otherProps
@@ -64,8 +65,8 @@ export function useBorderControlDropdown(
 	}, [ border, cx ] );
 
 	const popoverClassName = useMemo( () => {
-		return cx( styles.borderControlPopover );
-	}, [ cx ] );
+		return cx( styles.borderControlPopover, contentClassName );
+	}, [ cx, contentClassName ] );
 
 	const popoverControlsClassName = useMemo( () => {
 		return cx( styles.borderControlPopoverControls );

@@ -107,6 +107,13 @@ _Note: the value may be `undefined` if a user clears all border properties._
 
 - Required: Yes
 
+### `popoverContentClassName`: `string`
+
+A custom CSS class name to be assigned to the `BorderControl`'s dropdown
+popover content.
+
+- Required: No
+
 ### `shouldSanitizeBorder`: `boolean`
 
 If opted into, sanitizing the border means that if no width or color have been

@@ -43,6 +43,7 @@ const BorderControl = (
 		onSliderChange,
 		onWidthChange,
 		placeholder,
+		popoverContentClassName,
 		previousStyleSelection,
 		showDropdownHeader,
 		sliderClassName,
@@ -67,6 +68,7 @@ const BorderControl = (
 					<BorderControlDropdown
 						border={ border }
 						colors={ colors }
+						contentClassName={ popoverContentClassName }
 						disableCustomColors={ disableCustomColors }
 						enableAlpha={ enableAlpha }
 						enableStyle={ enableStyle }

@@ -123,7 +123,7 @@ export const borderControlPopover = css`
 `;
 
 export const borderControlPopoverControls = css`
-	padding: ${ space( 4 ) };
+	padding: ${ space( 2 ) };
 
 	> div:first-of-type > ${ StyledLabel } {
 		margin-bottom: 0;

@@ -80,6 +80,11 @@ export type BorderControlProps = ColorProps &
 		 * interaction that selects or clears, border color, style, or width.
 		 */
 		onChange: ( value?: Border ) => void;
+		/**
+		 * A custom CSS class name to be assigned to the border control's
+		 * dropdown popover content.
+		 */
+		popoverContentClassName?: string;
 		/**
 		 * If opted into, sanitizing the border means that if no width or color
 		 * have been selected, the border style is also cleared and `undefined`
@@ -118,6 +123,11 @@ export type DropdownProps = ColorProps & {
 	 * values for its popover controls.
 	 */
 	border?: Border;
+	/**
+	 * A custom CSS class name to be assigned to the border control's
+	 * dropdown popover content.
+	 */
+	contentClassName?: string;
 	/**
 	 * This controls whether to render border style options.
 	 *