Valo tabsheet problem when resizing

Hello Everyone,
I would like to know how to fix this problem. I have a vertical layout
say like this

VerticalLayout vl = new VerticalLayout();
TabSheet tabsheet = new TabSheet();

HorizontalLayout tab1 = createTab1();          
VerticalLayout tab2 = createTab2();              

this vl is wrapped again in a Layout and in placed in a verticallayout together with a horizontal layout and has “button”
added to confirm these tabs

tab1 has a form layout to display and tab2 has a table to display

The problem is when i try to open the tab the tabsheet with tab2 ,the layout is overflowing and the buttons are seen but they are not clickable. you can take a look at the attachment.

but this same problem does not arise when i use a monitor with greater resolution , also did not arise when i used reindeer theme.

// tried

  1. with overflow : visible for tabsheet, table,
  2. also tried setheightundefined. for tabs, parent layout, nothing worked

I am not sure where the problem is, Your help is greatly appreciated.