fix(ui5-multi-combobox): fix behavior of show all selected button (#2100)

Author: fifoosid

packages/main/src/MultiComboBox.js

@@ -335,9 +335,22 @@ class MultiComboBox extends UI5Element {
 	}
 
 	filterSelectedItems(event) {
+		if (this.allItemsSelected) {
+			this.filterSelected = true;
+			return;
+		}
+
 		this.filterSelected = event.target.pressed;
 	}
 
+	get _showAllItemsButtonPressed() {
+		return this.filterSelected || this.allItemsSelected;
+	}
+
+	get allItemsSelected() {
+		return this.items.length === this.selectedValues.length;
+	}
+
 	get _inputDom() {
 		return this.shadowRoot.querySelector("#ui5-multi-combobox-input");
 	}

packages/main/src/MultiComboBoxPopover.hbs

@@ -44,7 +44,8 @@
 					class="ui5-multi-combobox-toggle-button"
 					icon="multiselect-all"
 					design="Transparent"
-					?pressed={{filterSelected}}
+					?pressed={{_showAllItemsButtonPressed}}
+					?disabled={{allItemsSelected}}
 					@click="{{filterSelectedItems}}"
 				></ui5-togglebutton>
 		</div>