Why blank variable is shown in input settings?

<p id="isPasted">Double click on the text, select and delete it.</p><p>If you mean to have it blank as default, you need the source code to edit it directly in the code.</p>

<p id="isPasted">In trading platforms like TradingView (Pine Script) or MetaTrader (MQL4/MQL5), a "blank" or empty variable in the input settings usually serves one of two purposes: UI organization or functional logic.</p><p><strong>1. Visual Organization (The Most Common Use)</strong></p><p>Traders and developers often use "blank" input variables to make complex settings panels easier to read.</p><ul><li>Separators: A string input with no name or value can act as a visual break between different groups of settings (e.g., separating "Entry Logic" from "Risk Management").</li><li>Headings: Sometimes a variable is created with a title but no actual input field to act as a section header.</li><li>Cleanliness: In MetaTrader, developers may use a blank string variable to create "white space," which prevents the settings window from looking like a cluttered wall of text. </li></ul><p><strong>2. Functional "Default" Logic</strong></p><p>A blank input often acts as a trigger for the script to use a built-in default rather than a specific user-defined value.</p><ul><li>Symbol/Ticker: If a "Symbol" input is left blank, the script typically defaults to the asset currently on your chart. If you type something in, it overrides the chart symbol.</li><li>Timeframe: A blank timeframe input often tells the script to use the chart's current resolution (e.g., 5m, 1h) instead of a hardcoded one.</li><li>Placeholders: In some advanced tools, a blank field is where you can insert dynamic "placeholders" (like %bar_index%) to customize how data is displayed on the chart. </li></ul><p><strong>3. Disabling Features</strong></p><p>Leaving a variable blank or setting it to na (Not Available) can sometimes be a way to disable a specific feature without removing the indicator.</p><ul><li>Optional Levels: For example, an indicator might have slots for "Target 1," "Target 2," and "Target 3." Leaving "Target 3" blank tells the code to skip plotting that level.</li><li>Alert Messages: A blank "Alert Message" field might signify that no custom text should be sent when a trade is triggered. </li></ul><p><strong>4. Error Prevention (The "na" Value)</strong></p><p>In programming, if a calculation cannot be completed (e.g., a 200-period moving average on a chart with only 100 bars), the variable will show as "blank" or na. This is a safety mechanism to prevent the trading bot from making decisions based on "garbage" or incomplete data.&nbsp;</p>