For other nodes with tooltips, -fx-show-delay is not applied until their tooltips are displayed once, which happens using the default delay time of 1000 ms.

The attached test case, with just this css style:

.tooltip {
    -fx-show-delay: 10ms;
}

 shows the issue, after doing the following steps:

- Start application
- Hover over button 1 repeatedly (without waiting 1 second), see the output:


Tooltip 1 delay: 1000.0 ms
Tooltip 1 shown
Tooltip 1 shown
Tooltip 1 delay: 10.0 ms
Tooltip 1 shown
Tooltip 1 delay: 10.0 ms
Tooltip 1 shown
Tooltip 1 delay: 10.0 ms
Tooltip 1 shown
...

every time the mouse is over the button 1, the tooltip 1 is displayed, and with the expected 10 ms delay.

- Hover over button 2 repeatedly (without waiting 1 second), see the output:

Tooltip 2 delay: 1000.0 ms
Tooltip 2 delay: 1000.0 ms
Tooltip 2 delay: 1000.0 ms
Tooltip 2 delay: 1000.0 ms
...

the tooltip 2 is never displayed, which is unexpected.

- Hover over button 2 again, wait one second, and then enter/exit repeatedly (without waiting 1 second), see the output:

Tooltip 2 delay: 1000.0 ms
Tooltip 2 shown
Tooltip 2 delay: 10.0 ms
Tooltip 2 shown
Tooltip 2 delay: 10.0 ms
Tooltip 2 shown
Tooltip 2 delay: 10.0 ms
Tooltip 2 shown
 ...

After waiting one second, the tooltip 2 is displayed, and then it will always take the expected 10 ms.

There is a cssForced [1] flag that forces the CSS processing in TooltipBehavior, but that is only applied for the first tooltip that requires it, because TooltipBehavior is a static class shared by all nodes with tooltips.

(this CSS processing explains why the first time the tooltip 1 from the above test is displayed it is shown twice)

This issue can be reproduced with any JavaFX version since 9.

[1] https://github.com/openjdk/jfx/blob/master/modules/javafx.controls/src/main/java/javafx/scene/control/Tooltip.java#L1001