diff --git a/blocks/block-edit/index.js b/blocks/block-edit/index.js
index 7d497ba1217a34..97362d85c13087 100644
--- a/blocks/block-edit/index.js
+++ b/blocks/block-edit/index.js
@@ -15,8 +15,10 @@ function BlockEdit( props ) {
 	// `edit` and `save` are functions or components describing the markup
 	// with which a block is displayed. If `blockType` is valid, assign
 	// them preferencially as the render value for the block.
-	const Edit = blockType.edit || blockType.save;
-	Edit.displayName = 'Edit';
+	let Edit;
+	if ( blockType ) {
+		Edit = blockType.edit || blockType.save;
+	}
 
 	return applyFilters( 'BlockEdit', <Edit key="edit" { ...editProps } />, props );
 }
diff --git a/blocks/hooks/anchor.js b/blocks/hooks/anchor.js
index 149431318c6e04..88a8bb275dd4a6 100644
--- a/blocks/hooks/anchor.js
+++ b/blocks/hooks/anchor.js
@@ -6,7 +6,6 @@ import { assign } from 'lodash';
 /**
  * WordPress dependencies
  */
-import { concatChildren } from '@wordpress/element';
 import { __ } from '@wordpress/i18n';
 
 /**
@@ -55,9 +54,9 @@ export function addAttribute( settings ) {
  */
 export function addInspectorControl( element, props ) {
 	if ( hasBlockSupport( props.name, 'anchor' ) && props.focus ) {
-		element = concatChildren(
+		element = [
 			element,
-			<InspectorControls>
+			<InspectorControls key="inspector-anchor">
 				<InspectorControls.TextControl
 					label={ __( 'HTML Anchor' ) }
 					help={ __( 'Anchors lets you link directly to a section on a page.' ) }
@@ -69,8 +68,8 @@ export function addInspectorControl( element, props ) {
 							anchor: nextValue,
 						} );
 					} } />
-			</InspectorControls>
-		);
+			</InspectorControls>,
+		];
 	}
 
 	return element;
diff --git a/blocks/hooks/custom-class-name.js b/blocks/hooks/custom-class-name.js
index 2133197429c6f8..4cae9cd193e186 100644
--- a/blocks/hooks/custom-class-name.js
+++ b/blocks/hooks/custom-class-name.js
@@ -7,7 +7,6 @@ import classnames from 'classnames';
 /**
  * WordPress dependencies
  */
-import { concatChildren } from '@wordpress/element';
 import { __ } from '@wordpress/i18n';
 
 /**
@@ -46,9 +45,9 @@ export function addAttribute( settings ) {
  */
 export function addInspectorControl( element, props ) {
 	if ( hasBlockSupport( props.name, 'customClassName', true ) && props.focus ) {
-		element = concatChildren(
+		element = [
 			element,
-			<InspectorControls force>
+			<InspectorControls key="inspector-custom-classname">
 				<InspectorControls.TextControl
 					label={ __( 'Additional CSS Class' ) }
 					value={ props.attributes.className || '' }
@@ -58,8 +57,8 @@ export function addInspectorControl( element, props ) {
 						} );
 					} }
 				/>
-			</InspectorControls>
-		);
+			</InspectorControls>,
+		];
 	}
 
 	return element;
diff --git a/blocks/inspector-controls/index.js b/blocks/inspector-controls/index.js
index 6b59c69af1fa9a..f5db4830647cac 100644
--- a/blocks/inspector-controls/index.js
+++ b/blocks/inspector-controls/index.js
@@ -15,9 +15,9 @@ import TextControl from './text-control';
 import TextareaControl from './textarea-control';
 import ToggleControl from './toggle-control';
 
-export default function InspectorControls( { force = false, children } ) {
+export default function InspectorControls( { children } ) {
 	return (
-		<Fill name="Inspector.Controls" force={ force }>
+		<Fill name="Inspector.Controls">
 			{ children }
 		</Fill>
 	);
diff --git a/components/slot-fill/fill.js b/components/slot-fill/fill.js
index 45c7d15008199e..628e434bbf27d3 100644
--- a/components/slot-fill/fill.js
+++ b/components/slot-fill/fill.js
@@ -8,18 +8,25 @@ import { noop } from 'lodash';
  */
 import { Component, createPortal } from '@wordpress/element';
 
-/**
- * Internal dependencies
- */
-import withInstanceId from '../higher-order/with-instance-id';
+let occurrences = 0;
 
 class Fill extends Component {
+	componentWillMount() {
+		this.occurrence = ++occurrences;
+	}
+
 	componentDidMount() {
 		const { registerFill = noop } = this.context;
 
 		registerFill( this.props.name, this );
 	}
 
+	componentWillUpdate() {
+		if ( ! this.occurrence ) {
+			this.occurrence = ++occurrences;
+		}
+	}
+
 	componentWillUnmount() {
 		const { unregisterFill = noop } = this.context;
 
@@ -27,13 +34,13 @@ class Fill extends Component {
 	}
 
 	componentWillReceiveProps( nextProps ) {
-		const { name, force } = nextProps;
+		const { name } = nextProps;
 		const {
 			unregisterFill = noop,
 			registerFill = noop,
 		} = this.context;
 
-		if ( this.props.name !== name || force ) {
+		if ( this.props.name !== name ) {
 			unregisterFill( this.props.name, this );
 			registerFill( name, this );
 		}
@@ -47,6 +54,10 @@ class Fill extends Component {
 		}
 	}
 
+	resetOccurrence() {
+		this.occurrence = null;
+	}
+
 	render() {
 		const { getSlot = noop } = this.context;
 		const { name, children } = this.props;
@@ -65,4 +76,4 @@ Fill.contextTypes = {
 	unregisterFill: noop,
 };
 
-export default withInstanceId( Fill );
+export default Fill;
diff --git a/components/slot-fill/provider.js b/components/slot-fill/provider.js
index f746421e2986a0..55a3fa8be24424 100644
--- a/components/slot-fill/provider.js
+++ b/components/slot-fill/provider.js
@@ -1,7 +1,7 @@
 /**
  * External dependencies
  */
-import { pick, without, noop } from 'lodash';
+import { pick, sortBy, forEach, without, noop } from 'lodash';
 
 /**
  * WordPress dependencies
@@ -61,6 +61,7 @@ class SlotFillProvider extends Component {
 			this.fills[ name ],
 			instance
 		);
+		this.resetFillOccurrence( name );
 		this.forceUpdateSlot( name );
 	}
 
@@ -69,15 +70,19 @@ class SlotFillProvider extends Component {
 	}
 
 	getFills( name ) {
-		return this.fills[ name ];
+		return sortBy( this.fills[ name ], 'occurrence' );
+	}
+
+	resetFillOccurrence( name ) {
+		forEach( this.fills[ name ], ( instance ) => {
+			instance.resetOccurrence();
+		} );
 	}
 
 	forceUpdateFills( name ) {
-		if ( this.fills.hasOwnProperty( name ) ) {
-			this.fills[ name ].forEach( ( instance ) => {
-				instance.forceUpdate();
-			} );
-		}
+		forEach( this.fills[ name ], ( instance ) => {
+			instance.forceUpdate();
+		} );
 	}
 
 	forceUpdateSlot( name ) {
diff --git a/components/slot-fill/slot.js b/components/slot-fill/slot.js
index 4214e41756ea83..8dc373509a1d16 100644
--- a/components/slot-fill/slot.js
+++ b/components/slot-fill/slot.js
@@ -55,7 +55,7 @@ class Slot extends Component {
 		return (
 			<div ref={ this.bindNode }>
 				{ map( getFills( name ), ( fill ) => {
-					const fillKey = fill.props.instanceId;
+					const fillKey = fill.occurrence;
 					return Children.map( fill.props.children, ( child, childIndex ) => {
 						if ( ! child || isString( child ) ) {
 							return child;
diff --git a/components/slot-fill/test/slot.js b/components/slot-fill/test/slot.js
index a2253a3427bb18..95b60233758360 100644
--- a/components/slot-fill/test/slot.js
+++ b/components/slot-fill/test/slot.js
@@ -26,7 +26,7 @@ class Filler extends Component {
 	render() {
 		return [
 			<button key="1" type="button" onClick={ () => this.setState( { num: this.state.num + 1 } ) } />,
-			<Fill name={ this.props.name } key="2">{ this.state.num.toString() }</Fill>,
+			<Fill name={ this.props.name } key="2">{ this.props.text || this.state.num.toString() }</Fill>,
 		];
 	}
 }
@@ -96,4 +96,37 @@ describe( 'Slot', () => {
 
 		expect( element.find( 'Slot > div' ).html() ).toBe( '<div>2</div>' );
 	} );
+
+	it( 'should render in expected order', () => {
+		const element = mount(
+			<Provider>
+				<Slot name="egg" key="slot" />
+			</Provider>
+		);
+
+		element.setProps( {
+			children: [
+				<Slot name="egg" key="slot" />,
+				<Filler name="egg" key="first" text="first" />,
+				<Filler name="egg" key="second" text="second" />,
+			],
+		} );
+
+		element.setProps( {
+			children: [
+				<Slot name="egg" key="slot" />,
+				<Filler name="egg" key="second" text="second" />,
+			],
+		} );
+
+		element.setProps( {
+			children: [
+				<Slot name="egg" key="slot" />,
+				<Filler name="egg" key="first" text="first" />,
+				<Filler name="egg" key="second" text="second" />,
+			],
+		} );
+
+		expect( element.find( 'Slot > div' ).html() ).toBe( '<div>firstsecond</div>' );
+	} );
 } );