Replace requestFocus() by requestFocusInWindow() where applicable

The former gives focus to the window in which a component is present,
while the latter only changes the focus within the current window (not
focusing the window itself if it is not focused yet). Java documentation
recommends changing `requestFocusInWindow()` where possible, due to some
platform-dependent behaviour in `requestFocus()`.

When focusing the serial monitor and plotter, `requestFocus()` is still
used, since then the focused window *should* change.

Author: matthijskooijman

app/src/processing/app/Editor.java

@@ -1608,7 +1608,7 @@ public void selectTab(final int index) {
     SwingUtilities.invokeLater(() -> {
       codePanel.removeAll();
       codePanel.add(tabs.get(index), BorderLayout.CENTER);
-      tabs.get(index).requestFocus();  // get the caret blinking
+      tabs.get(index).requestFocusInWindow(); // get the caret blinking
       // For some reason, these are needed. Revalidate says it should be
       // automatically called when components are added or removed, but without
       // it, the component switched to is not displayed. repaint() is needed to

app/src/processing/app/EditorStatus.java

@@ -147,7 +147,7 @@ public void edit(String message, String dflt) {
     editField.setVisible(true);
     editField.setText(dflt);
     editField.selectAll();
-    editField.requestFocus();
+    editField.requestFocusInWindow();
 
     repaint();
   }

app/src/processing/app/EditorTab.java

@@ -600,9 +600,9 @@ public String getCurrentKeyword() {
   }
 
   @Override
-  public void requestFocus() {
+  public boolean requestFocusInWindow() {
     /** If focus is requested, focus the textarea instead. */
-    textarea.requestFocus();
+    return textarea.requestFocusInWindow();
   }
 
 }