Remove scrollbar from template instance and scrollbar customization

I have a template (with template canvas inside it). This template is used inside a template repeater. Every template instance in template repeater shows individual vertical scrollbar whenever there is more data in it. But customer wants to have only single vertical scrollbar which will be displayed when any of the instances has more data and which will control scrolling in all instances.

1. Is it possible to hide individual scrollbars have one common scrollbar for all instances?

Another requirement is to change the look and feel of scrollbar to match with overall theme of window. I ran below script on client startup event found here

from javax.swing import UIManager

from javax.swing.plaf import ColorUIResource, FontUIResource, InsetsUIResource, DimensionUIResource
from java.awt import Color, Dimension
from javax.swing import BorderFactory, ImageIcon

UIManager.put("ArrowButton.arrowColor",ColorUIResource(33,150,243))
UIManager.put("ArrowButton.arrowShadow",ColorUIResource(245,245,245))
UIManager.put("ArrowButton.background",ColorUIResource(245,245,245))
UIManager.put("ArrowButton.borderColor",ColorUIResource(245,245,245))
UIManager.put("ArrowButton.innerHighlight",ColorUIResource(245,245,245))
UIManager.put("ArrowButton.innerShadow",ColorUIResource(245,245,245))
UIManager.put("ArrowButton.rolloverIndicator",ColorUIResource(Color(0,0,0,0)))
UIManager.put("ScrollBar.background",ColorUIResource(245,245,245))
UIManager.put("ScrollBar.border",BorderFactory.createEmptyBorder())
UIManager.put("ScrollBar.isButtonRollover",False)
UIManager.put("ScrollBar.isThumbRollover",False)
UIManager.put("ScrollBar.thumbBackground",ColorUIResource(230,230,230))
UIManager.put("ScrollBar.thumbBorderColor",ColorUIResource(230,230,230))
UIManager.put("ScrollBar.thumbHighlight",ColorUIResource(224,224,224))
UIManager.put("ScrollBar.thumbRolloverBorderColor",ColorUIResource(224,224,224))
UIManager.put("ScrollBar.thumbShadow",ColorUIResource(224,224,224))
UIManager.put("ScrollBar.width",15)
UIManager.put("ScrollPane.background",ColorUIResource(250,250,250))
UIManager.put("ScrollPane.border",BorderFactory.createEmptyBorder())
UIManager.put("TextArea.border",BorderFactory.createEmptyBorder(10,10,10,10))

But above doesn’t seem to be working though.

2. Am I missing anything here?

I am using v8.0.12.

Thanks in advance!