diff --git a/src/misc_gui.cpp b/src/misc_gui.cpp
index 7495b71398..03dc1e2144 100644
--- a/src/misc_gui.cpp
+++ b/src/misc_gui.cpp
@@ -959,17 +959,7 @@ struct QueryStringWindow : public Window
 	QueryStringWindow(StringID str, StringID caption, uint max_bytes, uint max_chars, WindowDesc *desc, Window *parent, CharSetFilter afilter, QueryStringFlags flags) :
 			Window(desc), editbox(max_bytes, max_chars)
 	{
-		char *last_of = &this->editbox.text.buf[this->editbox.text.max_bytes - 1];
-		GetString(this->editbox.text.buf, str, last_of);
-		StrMakeValidInPlace(this->editbox.text.buf, last_of, SVS_NONE);
-
-		/* Make sure the name isn't too long for the text buffer in the number of
-		 * characters (not bytes). max_chars also counts the '\0' characters. */
-		while (Utf8StringLength(this->editbox.text.buf) + 1 > this->editbox.text.max_chars) {
-			*Utf8PrevChar(this->editbox.text.buf + strlen(this->editbox.text.buf)) = '\0';
-		}
-
-		this->editbox.text.UpdateSize();
+		this->editbox.text.Assign(str);
 
 		if ((flags & QSF_ACCEPT_UNCHANGED) == 0) this->editbox.orig = this->editbox.text.buf;
 
diff --git a/src/textbuf.cpp b/src/textbuf.cpp
index 151c753d92..7418cdf29a 100644
--- a/src/textbuf.cpp
+++ b/src/textbuf.cpp
@@ -388,8 +388,7 @@ Textbuf::~Textbuf()
  */
 void Textbuf::Assign(StringID string)
 {
-	GetString(this->buf, string, &this->buf[this->max_bytes - 1]);
-	this->UpdateSize();
+	this->Assign(GetString(string));
 }
 
 /**
@@ -398,7 +397,16 @@ void Textbuf::Assign(StringID string)
  */
 void Textbuf::Assign(const std::string_view text)
 {
-	strecpy(this->buf, text.data(), &this->buf[this->max_bytes - 1]);
+	const char *last_of = &this->buf[this->max_bytes - 1];
+	strecpy(this->buf, text.data(), last_of);
+	StrMakeValidInPlace(this->buf, last_of, SVS_NONE);
+
+	/* Make sure the name isn't too long for the text buffer in the number of
+	 * characters (not bytes). max_chars also counts the '\0' characters. */
+	while (Utf8StringLength(this->buf) + 1 > this->max_chars) {
+		*Utf8PrevChar(this->buf + strlen(this->buf)) = '\0';
+	}
+
 	this->UpdateSize();
 }