--- a/devtools/client/webconsole/test/mochitest/browser.ini
+++ b/devtools/client/webconsole/test/mochitest/browser.ini
@@ -336,17 +336,16 @@ subsuite = clipboard
 [browser_webconsole_shows_reqs_from_netmonitor.js]
 [browser_webconsole_shows_reqs_in_netmonitor.js]
 [browser_webconsole_sidebar_object_expand_when_message_pruned.js]
 [browser_webconsole_sourcemap_css.js]
 [browser_webconsole_sourcemap_error.js]
 [browser_webconsole_sourcemap_invalid.js]
 [browser_webconsole_sourcemap_nosource.js]
 [browser_webconsole_split.js]
-skip-if = (os == 'mac') || (os == 'linux' && !debug && bits == 64) || (os == 'win') # Bug 1454123 disabled on OS X, Windows and Linux64 for frequent failures
 [browser_webconsole_split_close_button.js]
 [browser_webconsole_split_escape_key.js]
 [browser_webconsole_split_focus.js]
 [browser_webconsole_split_persist.js]
 [browser_webconsole_stacktrace_location_debugger_link.js]
 [browser_webconsole_stacktrace_location_scratchpad_link.js]
 [browser_webconsole_strict_mode_errors.js]
 [browser_webconsole_string.js]

--- a/devtools/client/webconsole/test/mochitest/browser_webconsole_split.js
+++ b/devtools/client/webconsole/test/mochitest/browser_webconsole_split.js
@@ -19,31 +19,31 @@ add_task(async function() {
 
   await addTab(TEST_URI);
   await testConsoleLoadOnDifferentPanel();
   await testKeyboardShortcuts();
   await checkAllTools();
 
   info("Testing host types");
   checkHostType(Toolbox.HostType.BOTTOM);
-  checkToolboxUI();
+  await checkToolboxUI();
   await toolbox.switchHost(Toolbox.HostType.SIDE);
   checkHostType(Toolbox.HostType.SIDE);
-  checkToolboxUI();
+  await checkToolboxUI();
   await toolbox.switchHost(Toolbox.HostType.WINDOW);
 
   // checkHostType, below,  will open the meatball menu to read the "Split
   // console" menu item label. However, if we've just opened a new window then
   // on some platforms when we switch focus to the new window we might end up
   // triggering the auto-close behavior on the menu popup. To avoid that, wait
   // a moment before querying the menu.
   await new Promise(resolve => requestIdleCallback(resolve));
 
   checkHostType(Toolbox.HostType.WINDOW);
-  checkToolboxUI();
+  await checkToolboxUI();
   await toolbox.switchHost(Toolbox.HostType.BOTTOM);
 
   async function testConsoleLoadOnDifferentPanel() {
     info("About to check console loads even when non-webconsole panel is open");
 
     await openPanel("inspector");
     const webconsoleReady = toolbox.once("webconsole-ready");
     await toolbox.toggleSplitConsole();
@@ -111,17 +111,17 @@ add_task(async function() {
               ? "hide"
               : "split";
         }
 
         // Wait for menu to close
         toolbox.doc.addEventListener("popuphidden", () => {
           resolve(label);
         }, { once: true });
-        EventUtils.synthesizeKey("KEY_Escape");
+        EventUtils.sendKey("ESCAPE", toolbox.win);
       }, { once: true });
     });
   }
 
   async function checkWebconsolePanelOpened() {
     info("About to check special cases when webconsole panel is open.");
 
     // Start with console split, so we can test for transition to main panel.