fix some things

css/xterm.css

@@ -174,7 +174,7 @@
     text-decoration: line-through;
 }
 
-.xterm-screen .xterm-decorations .xterm-decoration {
+.xterm-screen .xterm-decoration {
 	z-index: 6;
 	position: absolute;
 }

src/browser/Terminal.ts

@@ -159,6 +159,7 @@ export class Terminal extends CoreTerminal implements ITerminal {
 
     this.linkifier = this._instantiationService.createInstance(Linkifier);
     this.linkifier2 = this.register(this._instantiationService.createInstance(Linkifier2));
+    this.decorationService = this.register(this._instantiationService.createInstance(DecorationService));
 
     // Setup InputHandler listeners
     this.register(this._inputHandler.onRequestBell(() => this.bell()));
@@ -174,8 +175,6 @@ export class Terminal extends CoreTerminal implements ITerminal {
 
     // Setup listeners
     this.register(this._bufferService.onResize(e => this._afterResize(e.cols, e.rows)));
-
-    this.decorationService = this.register(this._instantiationService.createInstance(DecorationService));
   }
 
   /**
@@ -1004,10 +1003,6 @@ export class Terminal extends CoreTerminal implements ITerminal {
   }
 
   public registerDecoration(decorationOptions: IDecorationOptions): IDecoration | undefined {
-    // Disallow decorations on the alt buffer
-    if (this.buffer !== this.buffers.normal) {
-      return undefined;
-    }
     return this.decorationService!.registerDecoration(decorationOptions);
   }
 

src/browser/public/Terminal.ts

@@ -173,9 +173,7 @@ export class Terminal implements ITerminalApi {
   }
   public registerDecoration(decorationOptions: IDecorationOptions): IDecoration | undefined {
     this._checkProposedApi();
-    if (decorationOptions.x) {
-      this._verifyIntegers(decorationOptions.x);
-    }
+    this._verifyPositiveInteger(decorationOptions.x);
     return this._core.registerDecoration(decorationOptions);
   }
   public addMarker(cursorYOffset: number): IMarker | undefined {
@@ -288,4 +286,10 @@ export class Terminal implements ITerminalApi {
       }
     }
   }
+
+  private _verifyPositiveInteger(value?: number): void {
+    if (value && (value === Infinity || isNaN(value) || value % 1 !== 0 || value < 0)) {
+      throw new Error('This API only accepts positive integers');
+    }
+  }
 }

src/browser/services/DecorationService.ts

@@ -115,9 +115,6 @@ class Decoration extends Disposable implements IDecoration {
     this._element.style.width = `${this._decorationOptions.width}px`;
     this._element.style.height = `${this._decorationOptions.height}px`;
     this._element.style.top = `${(this.marker.line - this._bufferService.buffers.active.ydisp) * this._renderService.dimensions.scaledCellHeight}px`;
-    if (this._decorationOptions.x && this._decorationOptions.x < 0) {
-      throw new Error(`Decoration options x value cannot be negative, but was ${this._decorationOptions.x}.`);
-    }
 
     if (this._decorationOptions.anchor === 'right') {
       this._element.style.right = this._decorationOptions.x ? `${this._decorationOptions.x * this._renderService.dimensions.scaledCellWidth}px` : '';

test/api/Terminal.api.ts

@@ -755,7 +755,7 @@ describe('API Integration Tests', function(): void {
         window.throwMessage = e.message;
       }
     `);
-      await pollFor(page, 'window.throwMessage', 'Decoration options x value cannot be negative, but was -2.');
+      await pollFor(page, 'window.throwMessage', 'This API only accepts positive integers');
       assert.equal(await page.evaluate(`document.querySelector('.xterm-screen .xterm-decoration')`), undefined);
     });
   });