FlatButtonUI weird border issues

[Frank-99]

I was trying to have a button with a toolBar style, but when I did this:

FlatButton button = new FlatButton();
button.setButtonType(ButtonType.toolBarButton);

I got a focusBorder, which a normal toolBarButton in a toolBar doesn't have:

So I played with settings and I found out that if I set these properties in the Laf file (or if I instead use setFocusable(false)):

Component.focusWidth = 0
Component.innerFocusWidth = 0
HelpButton.focusWidth = 0
HelpButton.innerFocusWidth = 0
Button.focusWidth = 0
Button.innerFocusWidth = 0
Button.default.focusWidth = 0
Button.default.innerFocusWidth = 0
Button.toolbar.focusWidth = 0
Button.toolbar.innerFocusWidth = 0

It fixes the issue, but I still noticed weird border insets/spacing:

So I tried with this button type:

button.setButtonType(ButtonType.borderless);

But with the properties set, I still get a focus border:

The only way to fix it that I found is to set it not focusable manually:
button.setFocusable(false);
which results in this:

This is what I was looking for, it doesn't feel intuitive, I thought I would achive this result by default just by setting the style to toolBarButton, so either I'm missing something or there is some weird logic around the focus border drawing...

[DevCharly]

...so either I'm missing something or there is some weird logic around the focus border drawing

You missed that buttons in JToolBar are not focusable by default.
If you make them focusable (e.g. ToolBar.focusableButtons = true) then they also have focus borders.

Button type toolBarButton is exactly the same as if the button is a child of JToolBar. See:

FlatLaf/flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatButtonUI.java

Lines 471 to 474 in 5e4f00f

	static boolean isToolBarButton( Component c ) {
	return c.getParent() instanceof JToolBar ||
	(c instanceof AbstractButton && BUTTON_TYPE_TOOLBAR_BUTTON.equals( getButtonTypeStr( (AbstractButton) c ) ));
	}

[Frank-99]

If you make them focusable (e.g. ToolBar.focusableButtons = true) then they also have focus borders.

and that'd be alright, but if I set all these parameters, the focus border still shows...
aren't these ment to disable it?

Component.focusWidth = 0
Component.innerFocusWidth = 0
HelpButton.focusWidth = 0
HelpButton.innerFocusWidth = 0
Button.focusWidth = 0
Button.innerFocusWidth = 0
Button.default.focusWidth = 0
Button.default.innerFocusWidth = 0
Button.toolbar.focusWidth = 0
Button.toolbar.innerFocusWidth = 0

[DevCharly]

Hmm, I don't see any focus border (from FlatLaf Theme Editor):

With focus border:

[Frank-99]

to me it does nothing... I don't understand

I'm on Java 21.0.7.0, Windows 11 24h4 and FlatLaf 3.6.1