Fix opacity handling for tile and vector layers

src/ol/renderer/canvas/Layer.js

@@ -17,6 +17,7 @@ import {
   getTopRight,
 } from '../../extent.js';
 import {createCanvasContext2D} from '../../dom.js';
+import {cssOpacity} from '../../css.js';
 
 /**
  * @abstract
@@ -88,7 +89,7 @@ class CanvasLayerRenderer extends LayerRenderer {
     let container, context;
     if (
       target &&
-      target.style.opacity === '' &&
+      target.style.opacity === cssOpacity(opacity) &&
       target.className === layerClassName
     ) {
       const canvas = target.firstElementChild;