Inno Setup components visual glitch

Question

There a visual bug in my installer, in components page. It looks fine before you starting to scroll page down, than it start looking like mess.

I thought that problem is somewhere in code, but recreated components section only on absolutely clean script and problem still here. Tried to change scaling options and to enable/disable WizardStyle=modern option, but with no result. How to fix it? Inno Setup 6.2.0, tried 5.x. Maybe there is problem in my Windows, I don't know.

[Components]
Name: lang; Description: "lang"; Flags: fixed      
Name: lang\en; Description: "en"; Flags: exclusive
Name: lang\ge; Description: "ge"; Flags: exclusive 

Name: master; Description: "master"; Flags: fixed   
Name: master\data; Description: "data"; Flags: exclusive
Name: master\data\fix; Description: "fix for data"; 
Name: master\data\fix\1; Description: "fix 1"; Flags:  exclusive
Name: master\data\fix\2; Description: "fix 2"; Flags:  exclusive
Name: master\data\fix\3; Description: "fix 3"; Flags:  exclusive
Name: master\legacy; Description: "legacy"; Flags: exclusive; 

Name: frontend; Description: "frontend"; Flags: fixed; 
Name: frontend\1; Description: "frontend 1"; Flags: exclusive  
Name: frontend\2; Description: "frontend 2"; Flags: exclusive 
Name: frontend\3; Description: "frontend 3"; Flags: exclusive 

Name: option1; Description: "option 1"; 
Name: option2; Description: "option 2"; 
Name: option3; Description: "option 3"; 


Name: option4; Description: "option 4"; 
Name: option5; Description: "option 5"; 
Name: option6; Description: "option 6"
Name: option6\1; Description: "option 6 ver 1"; Flags: exclusive
Name: option6\2; Description: "option 6 ver 1.2"; Flags: exclusive

Answer 1

I can partially reproduce this issue on latest Inno Setup 6.2.1 version.

What I did: I copied your code and pasted it into official Example1.iss. Then compiled the script and changed the selection with mouse and with mouse wheel.

Everything looks fine with WizardStyle=modern

Looks bad with WizardStyle=classic

I believe there is problem with compiling complex [Component] section, because when I try the official example which is quite simple, it works correctly for both modern + classic:

Name: "program"; Description: "Program Files"; Types: full compact custom; Flags: fixed
Name: "help"; Description: "Help File"; Types: full
Name: "readme"; Description: "Readme File"; Types: full
Name: "readme\en"; Description: "English"; Flags: exclusive
Name: "readme\de"; Description: "German"; Flags: exclusive

Solution for now is to simplify your [Components] section and wait for official fix. There is no limitations mentioned in help file, but apparently very complex structures are not supported.

Version details: