Why does JSplitPane automatically set its location?

[Allen]

There is a tree in the left container of JSplitPane. When the tree
loads data nodes, the split pane will
automatically set its location to avoid tree container displaying
horizontal scroll bar.

I want to turn this function off. Pls tell me how to do it. Thank you.

 

[Allen]

There is a tree in the left container of JSplitPane. When the tree
loads data nodes, the split pane will
automatically set its location to avoid tree container displaying
horizontal scroll bar.

I want to turn this function off. Pls tell me how to do it. Thank you.

Sorry. It is because I call JSplitPane.resetToPreferredSizes();
I forget this call.