Description:
As you grab a UI window to resize the content view from the program border, the inner contents in LOCalc UI often display a black window and require a full redraw of the inner UI contents. 

Major machine components affecting results
Gigabyte 1650 Super 4GB,i5-3450S(2.8ghz), 8GB ram

Perceptual Performance in comparison to notepad++ window drag
LibreOffice Calc. 
Perceptual scale: 100% = 60fps, 1%= 1fps or less
All resize operations update on click release or mouse movement stop, unfortunate.

Top left in-20% / out-20%
left in-20% / out-20%
Bottom left in-20% / out-20%
Top in-20% / out-20%
Top Right in-20% / out-20%
Right in-5% / out-5%
Bottom Right in-5% / out-5%
Bottom in-1% / out-1%

Opinion:
The reason I am submitting this, is the delayed update and black window on content resize gives the program(LOCalc) the feel that it is going to crash. It has not, which is great, and more than I can say for Excel. It would be a welcomed update if resizing became smooth as butter.


Steps to Reproduce:
1. Open LibreOffice Calc
2. Hold left click on any border of LibreOffice Calc
3. Drag border and watch window completely re-draw and display sub-standard performance

Actual Results:
The window contents refresh and update at a sub-optimal rate.

Expected Results:
The window contents should have resized the contents of the window at the vertical refresh rate of the monitor.


Reproducible: Always


User Profile Reset: Yes


OpenGL enabled: Yes

Additional Info:
Version: 6.4.6.2 (x64)
Build ID: 0ce51a4fd21bff07a5c061082cc82c5ed232f115
CPU threads: 4; OS: Windows 6.1 Service Pack 1 Build 7601; UI render: GL; VCL: win; 
Locale: en-US (en_US); UI-Language: en-US
Calc: CL