Someone else may have to verify this, in case I may just be doing something wrong, but it appears that when using $scope-reset-css:true in my custom theme's .scss file, the resultant CSS is incorrect, in that the following is being generated for each CSS rule:
Code:
.x-reset.x-some-class  { ... }
Instead of:
Code:
.x-reset .x-some-class  { ... }
(There is no space between .x-reset and the other class in the top snippet)

There is 2,195 occurrences of this pattern within the generated css file. Here's my full .scss that I am using to generate my theme (It is basically just a scoped version of the gray theme):
Code:
$scope-reset-css: true;
$compile-all: true;
$theme-name: 'gray';
$base-color: #ccc;
$font-family: arial,tahoma,verdana,sans-serif !default;


//panel
$panel-header-background-gradient: color-stops(#F0F0F0, #D7D7D7);
$panel-border-color: #D0D0D0;
$panel-header-color: #333;


$panel-frame-background-color: #f1f1f1;


//window
$window-background-color: #e8e8e8;
$window-header-color: #333;


//menu
$menu-item-active-background-color: darken(#f3f3f3, 5);
$menu-item-active-border-color: #9d9d9d;


//datepicker
$datepicker-header-background-color: #6f6f6f;
$datepicker-border-color: #585858;
$datepicker-th-background-color: #e9e9e9;
$datepicker-selected-item-background-color: #d8d8d8;
$datepicker-item-hover-background-color: transparent;


//progress bar
$progress-border-color: #8e8e8e;
$progress-background-color: #f1f1f1;
$progress-bar-background-color: #ababab;


//tips
$tip-base-color: $base-color;
$tip-background-color: #e7e7e7;


//grid
$grid-header-over-border-color: darken($base-color, 3);


//toolbar
$toolbar-background-gradient: color-stops(#e6e6e6, #efefef);
$toolbar-separator-color: #aca899;
$toolbar-text-color: #000;
$toolbar-background-color: #e6e6e6;


//btn group
$btn-group-background-color: #f0f0f0;
$btn-group-header-background-color: #dfdfdf;
$btn-group-border-color: #d0d0d0;
$btn-group-header-color: #666;


//form
$fieldset-header-color: #333;


$boundlist-border-color: #b5b8c8;


//acordion
$accordion-header-background-color: #e5e5e5;


//tabs
$tab-base-color: #eaeaea;
$tab-color-active: #333333;


$tab-background-gradient: color-stops(#dcdcdc, #eaeaea);
$tab-background-gradient-over: 'tab-over' !default;
$tab-background-gradient-active: color-stops(#ffffff, #eaeaea);
$tab-background-gradient-disabled: 'tab-disabled' !default;


//buttons
$button-default-base-color: #f8f8f8;
$button-default-base-color-over: #f3f3f3;
$button-default-base-color-focus: $button-default-base-color-over;
$button-default-base-color-pressed: #d6d6d6;
$button-default-base-color-disabled: adjust-color($base-color, $hue: 0deg, $saturation: -55.556%, $lightness: 12.745%) !default; //F7F7F7


$button-default-border-color: #bbbbbb;
$button-default-border-color-over: #9d9d9d;
$button-default-border-color-focus: $button-default-border-color-over;
$button-default-border-color-pressed: $button-default-border-color-over;
$button-default-border-color-disabled: adjust-color($button-default-base-color-disabled, $hue: 0deg, $saturation: 0%, $lightness: -8.627%) !default;


$button-default-background-gradient: 'matte';
$button-default-background-gradient-over: 'matte';
$button-default-background-gradient-focus: 'matte';
$button-default-background-gradient-pressed: 'matte-reverse';
$button-default-background-gradient-disabled: 'matte';


$button-default-background-gradient-color-stops: null;
$button-default-background-gradient-color-stops-over: null;
$button-default-background-gradient-color-stops-focus: null;
$button-default-background-gradient-color-stops-pressed: null;
$button-default-background-gradient-color-stops-disabled: null;




$button-toolbar-base-color: $button-default-base-color;


$button-toolbar-border-color: transparent !default;
$button-toolbar-border-color-over: $button-default-border-color-over;
$button-toolbar-border-color-focus: $button-default-border-color-focus;
$button-toolbar-border-color-pressed: $button-default-border-color-pressed;
$button-toolbar-border-color-disabled: $button-default-border-color-disabled;


$button-toolbar-background-color: transparent !default;
$button-toolbar-background-color-over: $button-default-base-color-over;
$button-toolbar-background-color-focus: $button-default-base-color-focus;
$button-toolbar-background-color-pressed: $button-default-base-color-pressed;
$button-toolbar-background-color-disabled: transparent;


$button-toolbar-background-gradient: null;
$button-toolbar-background-gradient-over: 'matte';
$button-toolbar-background-gradient-focus: 'matte';
$button-toolbar-background-gradient-pressed: 'matte-reverse';
$button-toolbar-background-gradient-disabled: null;


$button-toolbar-background-gradient-color-stops: null;
$button-toolbar-background-gradient-color-stops-over: null;
$button-toolbar-background-gradient-color-stops-focus: null;
$button-toolbar-background-gradient-color-stops-pressed: null;
$button-toolbar-background-gradient-color-stops-disabled: null;


@import 'compass';
@import 'ext4/default/all';
This is using the Beta 2 build, FYI.