Layout loop caused by FlatTitlePane

[ingokegel]

I'm hitting a layout loop that is triggered by FlatTitlePane::menuBarLayouted calling revalidate() thereby somehow triggering a layout on the JRootPane. I'm not sure how this can happen, but I see this deterministically in some places in my automated UI tests that use AssertJ Swing as a framework. The async stack trace chain in IntelliJ looks like this:

and continues like that until IntelliJ truncates it. When this layout loop is triggered for the first time, it continues until the frame is closed. I notice this because the testing framework will become extremely slow in this case. The custom repaint manager in the stack trace is just for me to set a breakpoint, it also happens without it.

Passing the VM parameter -Dflatlaf.useWindowDecorations prevents this problem, but this is obviously not desirable.

My workaround is to set

UIManager.put("RootPaneUI", CustomFlatRootPaneUI.class.getName());

with

public static class CustomFlatRootPaneUI extends FlatRootPaneUI {
    @SuppressWarnings("unused")
    public static ComponentUI createUI(JComponent c ) {
        return new CustomFlatRootPaneUI();
    }

    @Override
    protected FlatTitlePane createTitlePane() {
        return new FlatTitlePane(rootPane) {
            @Override
            protected void menuBarLayouted() {
                updateNativeTitleBarHeightAndHitTestSpotsLater();
            }
        };
    }
}

which effectively just removes the revalidate() call from FlatTitlePane::menuBarLayouted. I don't see any negative effects from that removal.

[DevCharly]

Thanks for reporting/debugging this issue.
Have not seen this before, but invoking revalidate() from layout() was obviously a bad idea...

I've added the call to revalidate() in commit 30c7b44

It was necessary to update the layout when adding components to the menu bar.

With test app FlatWindowDecorationsTest it is possible to test it. When selecting the "right aligned stretching component" checkbox, a glue component and a progress bar are added to the menubar/title bar.

Before:

With revalidate() the title label is moved:

Without revalidate() the title label is missing:

Anyway, need to find a solution without revalidate()...

[DevCharly]

Replacing revalidate() with doLayout() works for me and should also fix the layout loop.

Could you please add doLayout() to your CustomFlatRootPaneUI ... menuBarLayouted() method and check whether the layout loop is gone?

[ingokegel]

Just checked with one of my UI tests where the layout loop was always reproducible and calling doLayout() instead of revalidate() does not trigger the layout loop.

[DevCharly]

Fixed in 1.6.2. Thanks.