.editor,
.viewer {
    margin:0;
    padding:0;
    text-align:center;
}
#canvas-container {
    margin:0.5em;
}


.ui-content { margin:0; padding: 0; }
.ui-grid-a { margin:0; padding: 0; }
#session-editor { margin:0; padding: 0; }
#session-viewer { margin:0; padding: 0; }
#current_color {border:1px solid #ffffff; margin-right: 0.5em;}

.editor,
.viewer {
    margin:0;
    padding:0;
    text-align:center;
}
#canvas-container {
    margin:0.4em;
}


.ui-content { margin:0; padding: 0; }
.ui-grid-a { margin:0; padding: 0; }
#session-editor { margin:0; padding: 0; }
#session-viewer { margin:0; padding: 0; }
#current_color {border:1px solid #ffffff; margin-right: 0.5em;}

Reduce margin to avoid scroll.
Reduce margin to avoid scroll.
