message: [WebGL Renderer] Fill in the gap on the right side of the char canvas
diff: @@ -243,11 +243,26 @@ export class WebGLCharRenderCanvas implements Disposable {
  this._canvas.height = this._canvasHeightPx;
  this._canvasCtx = this._canvas.getContext("2d", {alpha: this._transparentBackground});
  + this._paintInRightGapBackground();
  +
  if (debugParentElement != null) {
  debugParentElement.appendChild(this._canvas);
  }
  }
  + private _paintInRightGapBackground(): void {
  + const gapPx = this._canvasWidthPx - this._widthChars * this.cellWidthPx;
  + if (gapPx !== 0) {
  + const ctx = this._canvasCtx;
  + ctx.save();
  + const bgColor = RGBAToCss(this._palette[PALETTE_BG_INDEX]);
  + ctx.fillStyle = bgColor;
  + ctx.globalCompositeOperation = "source-over";
  + this._canvasCtx.fillRect(this.cellWidthPx * this._widthChars, 0, gapPx, this._canvasHeightPx);
  + ctx.restore();
  + }
  + }
  +
  dispose(): void {
  for (const d of this._disposables) {
  d.dispose();
  @@ -267,6 +282,7 @@ export class WebGLCharRenderCanvas implements Disposable {
  this._palette = palette;
  this._cellGrid.setPalette(this._palette);
  this._webglRenderer.setCursorColor(this._palette[PALETTE_CURSOR_INDEX]);
  + this._paintInRightGapBackground();
  }
  setCursorStyle(cursorStyle: CursorStyle): void {
  