Add quit button to element zapper mode

Related issue:
uBlockOrigin/uBlock-issues#1968

Given the availability of this new quit button, the element zapper
will now default to stick around after zapping an element.

Author: gorhill

src/css/epicker-ui.css

@@ -16,7 +16,7 @@ html#ublock0-epicker,
     border: 1px solid var(--border-2);
     box-sizing: border-box;
     cursor: default;
-    display: none;
+    display: flex;
     flex-direction: column;
     max-width: min(32rem, 100vw - 4px);
     min-width: min(24rem, 100vw - 4px);
@@ -25,8 +25,18 @@ html#ublock0-epicker,
     width: min(32rem, 100vw - 4px);
     z-index: 100;
 }
-#ublock0-epicker:not(.zap) aside {
-    display: flex;
+#ublock0-epicker.zap aside {
+    min-width: unset !important;
+    width: unset !important;
+}
+#ublock0-epicker.zap aside > section,
+#ublock0-epicker.zap aside > ul,
+#ublock0-epicker.zap aside > #windowbar > div:not(#quit) {
+    display: none;
+}
+#ublock0-epicker.zap aside > #windowbar > #quit {
+    height: 2.5em;
+    width: 2.5em;
 }
 #ublock0-epicker:not(.paused) aside,
 #ublock0-epicker.minimized aside {

src/js/epicker-ui.js

@@ -331,7 +331,7 @@ const onSvgClicked = function(ev) {
             mx: ev.clientX,
             my: ev.clientY,
             options: {
-                stay: ev.shiftKey || ev.type === 'touch',
+                stay: true,
                 highlight: ev.target !== svgIslands,
             },
         });
@@ -822,6 +822,8 @@ const startPicker = function() {
 
     unpausePicker();
 
+    $id('quit').addEventListener('click', onQuitClicked);
+
     if ( pickerRoot.classList.contains('zap') ) { return; }
 
     cmEditor.on('changes', onCandidateChanged);
@@ -837,7 +839,6 @@ const startPicker = function() {
             dom.cl.toggle(pickerRoot, 'minimized');
         }
     });
-    $id('quit').addEventListener('click', onQuitClicked);
     $id('move').addEventListener('mousedown', onStartMoving);
     $id('move').addEventListener('touchstart', onStartMoving);
     $id('candidateFilters').addEventListener('click', onCandidateClicked);