diff --git a/docs/framework/guides/deep-dive/schema.md b/docs/framework/guides/deep-dive/schema.md
index f3e06c6e0..8222e2391 100644
--- a/docs/framework/guides/deep-dive/schema.md
+++ b/docs/framework/guides/deep-dive/schema.md
@@ -57,7 +57,8 @@ schema.register( '$block', {
 	isBlock: true
 } );
 schema.register( '$text', {
-	allowIn: '$block'
+	allowIn: '$block',
+	isInline: true
 } );
 ```
 
diff --git a/src/model/model.js b/src/model/model.js
index 3c970ab29..500de84ae 100644
--- a/src/model/model.js
+++ b/src/model/model.js
@@ -94,7 +94,8 @@ export default class Model {
 			isBlock: true
 		} );
 		this.schema.register( '$text', {
-			allowIn: '$block'
+			allowIn: '$block',
+			isInline: true
 		} );
 		this.schema.register( '$clipboardHolder', {
 			allowContentOf: '$root',
diff --git a/src/model/schema.js b/src/model/schema.js
index a4a4f8b40..3745c143d 100644
--- a/src/model/schema.js
+++ b/src/model/schema.js
@@ -230,7 +230,7 @@ export default class Schema {
 
 	/**
 	 * Returns `true` if the given item is defined to be
-	 * a object element by {@link module:engine/model/schema~SchemaItemDefinition}'s `isObject` property.
+	 * an object element by {@link module:engine/model/schema~SchemaItemDefinition}'s `isObject` property.
 	 *
 	 *		schema.isObject( 'paragraph' ); // -> false
 	 *		schema.isObject( 'image' ); // -> true
@@ -246,6 +246,24 @@ export default class Schema {
 		return !!( def && def.isObject );
 	}
 
+	/**
+	 * Returns `true` if the given item is defined to be
+	 * a object element by {@link module:engine/model/schema~SchemaItemDefinition}'s `isInline` property.
+	 *
+	 *		schema.isInline( 'paragraph' ); // -> false
+	 *		schema.isInline( 'softBreak' ); // -> true
+	 *
+	 *		const text = writer.createText('foo' );
+	 *		schema.isObject( text ); // -> true
+	 *
+	 * @param {module:engine/model/item~Item|module:engine/model/schema~SchemaContextItem|String} item
+	 */
+	isInline( item ) {
+		const def = this.getDefinition( item );
+
+		return !!( def && def.isInline );
+	}
+
 	/**
 	 * Checks whether the given node (`child`) can be a child of the given context.
 	 *
@@ -899,7 +917,7 @@ mix( Schema, ObservableMixin );
  * * `allowAttributesOf` – A string or an array of strings. Inherits attributes from other items.
  * * `inheritTypesFrom` – A string or an array of strings. Inherits `is*` properties of other items.
  * * `inheritAllFrom` – A string. A shorthand for `allowContentOf`, `allowWhere`, `allowAttributesOf`, `inheritTypesFrom`.
- * * Additionally, you can define the following `is*` properties: `isBlock`, `isLimit`, `isObject`. Read about them below.
+ * * Additionally, you can define the following `is*` properties: `isBlock`, `isLimit`, `isObject`, `isInline`. Read about them below.
  *
  * # The is* properties
  *
@@ -915,6 +933,8 @@ mix( Schema, ObservableMixin );
  * a limit element are limited to its content. **Note:** All objects (`isObject`) are treated as limit elements, too.
  * * `isObject` – Whether an item is "self-contained" and should be treated as a whole. Examples of object elements:
  * `image`, `table`, `video`, etc. **Note:** An object is also a limit, so
+ * * `isInline` – Whether an item is "text-like" and should be treated as an inline text. Examples of inline elements:
+ * `text`, `softBreak` (`<br>`), etc.
  * {@link module:engine/model/schema~Schema#isLimit `isLimit()`}
  * returns `true` for object elements automatically.
  *
@@ -931,7 +951,8 @@ mix( Schema, ObservableMixin );
  *			isBlock: true
  *		} );
  *		this.schema.register( '$text', {
- *			allowIn: '$block'
+ *			allowIn: '$block',
+ *			isInline: true
  *		} );
  *
  * They reflect typical editor content that is contained within one root, consists of several blocks
diff --git a/tests/model/schema.js b/tests/model/schema.js
index 2b7b53eb3..63febea29 100644
--- a/tests/model/schema.js
+++ b/tests/model/schema.js
@@ -376,6 +376,41 @@ describe( 'Schema', () => {
 		} );
 	} );
 
+	describe( 'isInline()', () => {
+		it( 'returns true if an item was registered as inline', () => {
+			schema.register( 'foo', {
+				isInline: true
+			} );
+
+			expect( schema.isInline( 'foo' ) ).to.be.true;
+		} );
+
+		it( 'returns false if an item was registered as a limit (because not all limits are objects)', () => {
+			schema.register( 'foo', {
+				isLimit: true
+			} );
+
+			expect( schema.isInline( 'foo' ) ).to.be.false;
+		} );
+
+		it( 'returns false if an item was not registered as an object', () => {
+			schema.register( 'foo' );
+
+			expect( schema.isInline( 'foo' ) ).to.be.false;
+		} );
+
+		it( 'returns false if an item was not registered at all', () => {
+			expect( schema.isInline( 'foo' ) ).to.be.false;
+		} );
+
+		it( 'uses getDefinition()\'s item to definition normalization', () => {
+			const stub = sinon.stub( schema, 'getDefinition' ).returns( { isInline: true } );
+
+			expect( schema.isInline( 'foo' ) ).to.be.true;
+			expect( stub.calledOnce ).to.be.true;
+		} );
+	} );
+
 	describe( 'checkChild()', () => {
 		beforeEach( () => {
 			schema.register( '$root' );
@@ -2468,7 +2503,8 @@ describe( 'Schema', () => {
 			},
 			() => {
 				schema.extend( '$text', {
-					allowAttributes: [ 'bold', 'italic' ]
+					allowAttributes: [ 'bold', 'italic' ],
+					isInline: true
 				} );
 
 				// Disallow bold in heading1.
@@ -2494,7 +2530,8 @@ describe( 'Schema', () => {
 				isBlock: true
 			} );
 			schema.register( '$text', {
-				allowIn: '$block'
+				allowIn: '$block',
+				isInline: true
 			} );
 
 			for ( const definition of definitions ) {
@@ -2738,40 +2775,53 @@ describe( 'Schema', () => {
 			expect( schema.checkAttribute( r1i, 'alignment' ) ).to.be.false;
 		} );
 
+		it( '$text is inline', () => {
+			expect( schema.isLimit( '$text' ) ).to.be.false;
+			expect( schema.isBlock( '$text' ) ).to.be.false;
+			expect( schema.isObject( '$text' ) ).to.be.false;
+			expect( schema.isInline( '$text' ) ).to.be.true;
+		} );
+
 		it( '$root is limit', () => {
 			expect( schema.isLimit( '$root' ) ).to.be.true;
 			expect( schema.isBlock( '$root' ) ).to.be.false;
 			expect( schema.isObject( '$root' ) ).to.be.false;
+			expect( schema.isInline( '$root' ) ).to.be.false;
 		} );
 
 		it( 'paragraph is block', () => {
 			expect( schema.isLimit( 'paragraph' ) ).to.be.false;
 			expect( schema.isBlock( 'paragraph' ) ).to.be.true;
 			expect( schema.isObject( 'paragraph' ) ).to.be.false;
+			expect( schema.isInline( '$root' ) ).to.be.false;
 		} );
 
 		it( 'heading1 is block', () => {
 			expect( schema.isLimit( 'heading1' ) ).to.be.false;
 			expect( schema.isBlock( 'heading1' ) ).to.be.true;
 			expect( schema.isObject( 'heading1' ) ).to.be.false;
+			expect( schema.isInline( '$root' ) ).to.be.false;
 		} );
 
 		it( 'listItem is block', () => {
 			expect( schema.isLimit( 'listItem' ) ).to.be.false;
 			expect( schema.isBlock( 'listItem' ) ).to.be.true;
 			expect( schema.isObject( 'listItem' ) ).to.be.false;
+			expect( schema.isInline( '$root' ) ).to.be.false;
 		} );
 
 		it( 'image is block object', () => {
 			expect( schema.isLimit( 'image' ) ).to.be.true;
 			expect( schema.isBlock( 'image' ) ).to.be.true;
 			expect( schema.isObject( 'image' ) ).to.be.true;
+			expect( schema.isInline( '$root' ) ).to.be.false;
 		} );
 
 		it( 'caption is limit', () => {
 			expect( schema.isLimit( 'caption' ) ).to.be.true;
 			expect( schema.isBlock( 'caption' ) ).to.be.false;
 			expect( schema.isObject( 'caption' ) ).to.be.false;
+			expect( schema.isInline( '$root' ) ).to.be.false;
 		} );
 	} );
 
diff --git a/tests/model/utils/selection-post-fixer.js b/tests/model/utils/selection-post-fixer.js
index 328978ade..9ce86a5a2 100644
--- a/tests/model/utils/selection-post-fixer.js
+++ b/tests/model/utils/selection-post-fixer.js
@@ -945,6 +945,47 @@ describe( 'Selection post-fixer', () => {
 			} );
 		} );
 
+		describe( 'non-collapsed selection - inline widget scenarios', () => {
+			beforeEach( () => {
+				model.schema.register( 'placeholder', {
+					allowWhere: '$text',
+					isInline: true
+				} );
+			} );
+
+			it( 'should fix selection that ends in inline element', () => {
+				setModelData( model, '<paragraph>aaa[<placeholder>]</placeholder>bbb</paragraph>' );
+
+				expect( getModelData( model ) ).to.equal( '<paragraph>aaa[]<placeholder></placeholder>bbb</paragraph>' );
+			} );
+
+			it( 'should fix selection that starts in inline element', () => {
+				setModelData( model, '<paragraph>aaa<placeholder>[</placeholder>]bbb</paragraph>' );
+
+				expect( getModelData( model ) ).to.equal( '<paragraph>aaa<placeholder></placeholder>[]bbb</paragraph>' );
+			} );
+
+			it( 'should fix selection that ends in inline element that is also an object', () => {
+				model.schema.extend( 'placeholder', {
+					isObject: true
+				} );
+
+				setModelData( model, '<paragraph>aaa[<placeholder>]</placeholder>bbb</paragraph>' );
+
+				expect( getModelData( model ) ).to.equal( '<paragraph>aaa[<placeholder></placeholder>]bbb</paragraph>' );
+			} );
+
+			it( 'should fix selection that starts in inline element that is also an object', () => {
+				model.schema.extend( 'placeholder', {
+					isObject: true
+				} );
+
+				setModelData( model, '<paragraph>aaa<placeholder>[</placeholder>]bbb</paragraph>' );
+
+				expect( getModelData( model ) ).to.equal( '<paragraph>aaa[<placeholder></placeholder>]bbb</paragraph>' );
+			} );
+		} );
+
 		describe( 'collapsed selection', () => {
 			beforeEach( () => {
 				setModelData( model,