Empty tooltips showing on screen

[Nibby]

When a component has an empty tooltip set, an empty tooltip bubble is drawn. For example:

JButton c = new JButton("Tooltip Test");
c.setToolTipText("");

Setting the tooltip text to null disables this. This is quite different form other LaFs, where an empty tooltip is not shown.

[Poivin]

Yes i noticed that too. in my app i have tooltips with empty string inside and they were invisible before using flatLAF.

[DevCharly]

Thx for reporting. I agree that is does not make any sense to show empty tips. This is now fixed in master branch.

But this is actually a problem in Swing because it always creates a JToolTip as soon as JComponent.getToolTipText() != null.
(see https://github.com/openjdk/jdk/blob/bcff4990ad9db20d11c59841a409717118645a65/src/java.desktop/share/classes/javax/swing/ToolTipManager.java#L691-L694). So the only chance to "hide" the empty tooltip was setting its preferred size to 0,0.

I wonder what LaFs you're using that do not show empty tips. I tried Metal, Nimbus, Substance, Windows and Mac L&F and all showed empty tips...

[Poivin]

Thx DevCharly!
I used Motif LaF and juste verified it again with the same code.
Edit : maybe somewhere in my hmi framework i have a setPreferredSize when using motif LaF...

[DevCharly]

@Poivin maybe you did not notice it because is is a small dot hidden by the mouse pointer. Move the mouse slightly to the right and you probably see it (Java 8):

Windows LaF (Java 8):

In Java 14 the empty tips are much larger and not hidden by the mouse pointer:

[DevCharly]

So generally I would recommend using null for toolTipText instead of empty strings 😉