core: Revisit drag+drop into the editor. Works better but not as I intended. Use it just to update the screenshot in the welcome app.

core/client.js

@@ -411,6 +411,7 @@ class TfFilesElement extends LitElement {
 			current: {type: String},
 			files: {type: Object},
 			dropping: {type: Number},
+			drop_target: {type: String},
 		};
 	}
 
@@ -449,6 +450,9 @@ class TfFilesElement extends LitElement {
 		if (!this.files[file].clean) {
 			classes.push('dirty');
 		}
+		if (this.drop_target == file) {
+			classes.push('drop');
+		}
 		return html`<div
 			class="${classes.join(' ')}"
 			@click=${(x) => this.file_click(file)}
@@ -465,11 +469,12 @@ class TfFilesElement extends LitElement {
 		event.preventDefault();
 		event.stopPropagation();
 		this.dropping = 0;
+		this.drop_target = undefined;
 		for (let file of event.dataTransfer.files) {
 			let buffer = await file.arrayBuffer();
 			let text = new TextDecoder('latin1').decode(buffer);
 			gFiles[file.name] = {
-				doc: new cm6.EditorState.create({
+				doc: cm6.EditorState.create({
 					doc: text,
 					extensions: cm6.extensions,
 				}),
@@ -488,6 +493,7 @@ class TfFilesElement extends LitElement {
 	 */
 	drag_enter(event) {
 		this.dropping++;
+		this.drop_target = event.srcElement.innerText.trim();
 		event.preventDefault();
 	}
 
@@ -497,6 +503,13 @@ class TfFilesElement extends LitElement {
 	 */
 	drag_leave(event) {
 		this.dropping--;
+		if (this.dropping == 0) {
+			this.drop_target = undefined;
+		}
+	}
+
+	drag_over(event) {
+		event.preventDefault();
 	}
 
 	/**
@@ -523,6 +536,10 @@ class TfFilesElement extends LitElement {
 					background-color: #2aa198;
 				}
 
+				div.file.drop {
+					border: 4px solid red;
+				}
+
 				div.file.dirty::after {
 					content: '*';
 				}
@@ -531,20 +548,12 @@ class TfFilesElement extends LitElement {
 				@drop=${this.drop}
 				@dragenter=${this.drag_enter}
 				@dragleave=${this.drag_leave}
+				@dragover=${this.drag_over}
 			>
 				${Object.keys(this.files)
 					.sort()
 					.map((x) => self.render_file(x))}
 			</div>
-			<div
-				?hidden=${this.dropping == 0}
-				@drop=${this.drop}
-				@dragenter=${this.drag_enter}
-				@dragleave=${this.drag_leave}
-				style="text-align: center; vertical-align: middle; outline: 16px solid red; margin: -8px; background-color: rgba(255, 0, 0, 0.5); position: absolute; left: 16px; top: 16px; width: calc(100% - 16px); height: calc(100% - 16px); z-index: 1000"
-			>
-				Drop File(s)
-			</div>
 		`;
 	}
 }